Talk:Gregorian calendar/Archive 4

centuries have only one date for beginning and ending.
all centuries begin on January 1st on a year that ends with '01 and ends on December 31st with a year that ends with '00. Any other way is totally 100% wrong. Thus the 20th century began with January 1, 1901, and ended on December 31, 2000. That is why it was the 20th century. because it end with 20(00). This is the 21st century, because it started on January 1, 2001 and not on January 1, 2000, because that was the beginning of the last year of the last century. This is this century and it did start on January 1, 2001 and not before. And this century will end on December 31, 2100, because it ends the year with 21(00), not with December 31, 2099. This is the 21st century and that means it ends with the year 2100. It has nothing to do with leap years of anything else. The celebration that celebrated around the world at the beginning of this century was actually a whole year way to early. The majority of people and governments just plainly goofed up. Just like this decade starts on January 1, 2011 and it ends on December 31, 2020, not 2019 like too man people are already thinking about. I wish people would get this right.Bobbyr55 (talk) 01:46, 31 December 2014 (UTC)

Last country to adopt the Gregorian calendar?
It says here that the last country to adopt the Gregorian calendar was the Soviet Union in 1929. I found articles (referred below) that mention that the Soviet Union changed to the Gregorian calendar on February 14, 1918. In fact, I found articles stating that the USSR actually abandoned the Gregorian calendar in 1929 in favour of the "Eternal Calendar" consisting of 12 months, each made up of 30 days split into six 5-day weeks. Later in 1932 they switched to 6-day weeks, only coming back to the Gregorian proper in 1940. Can someone please check these facts and edit the page? I've put some of the links below. The first one is pretty comprehensive, but the others will help you double check.

http://www.sras.org/russian_holidays

https://www.worldslastchance.com/ecourses/lessons/changing-weeks-hiding-sabbath-ecourse/18/20th-century-soviet-calendar-reform.html

http://history1900s.about.com/od/1920s/a/sovietcalendar.htm

So does that make it the last country to adopt the Gregorian calendar (i.e. in 1940) or does that title pass to someone else? — Preceding unsigned comment added by 14.97.86.240 (talk) 18:33, 13 February 2015 (UTC)


 * There is certainly some confusion that needs to be sorted out. Adoption of the Gregorian calendar says that Russia adopted it in February 1918.


 * The graphical Timeline says that Russia adopted it in 1918; it also says that the Soviet Union did so in 1922. That seems wrong for starters.  Russia had already converted almost 5 years before the USSR ever came into formal existence in 1922, so it's not like the USSR started out under the Julian calendar and only later switched to Gregorian.  No, the pre-existing Russian change-over simply extended to the new political entity that came into existence on 30 December 1922, and that cannot be characterised as an "adoption".


 * Then there was the Soviet calendar, which was in use between 1929 and 1940. That means that 1929 is the year that the Soviets abandoned the Gregorian, not adopted it.  (The relevance of 1930 escapes me entirely.)  Whether the re-adoption counts for the purposes of saying which was the last country to make the switch, I'm not sure, but if it does count, the relevant date would be 1940, not 1929.  For comparison, when the French abandoned the French Republican Calendar in 1805 after 12 years of use, and re-adopted the Gregorian, we don't quote 1805 as the date of Gregorian adoption in France.  We always refer to its original adoption there in 1582. So why make an exception for the Soviet Union?  The fact that the country's name and organisation changed matters not.


 * I prefer to say that Russia adopted the Gregorian in 1918; the Soviet interruption 1929-40 deserves a mention later in the article and a link to Soviet calendar, but let us please get the dates right. --   Jack of Oz   [pleasantries]  21:43, 13 February 2015 (UTC)


 * I've been bold and made the above changes. But still feel free to discuss.  --   Jack of Oz   [pleasantries]  23:10, 13 February 2015 (UTC)


 * The expert on this is Joe Kress.  Feel free to ping him.   See Soviet calendar where he makes it clear by references to the date on the pages of e.g. Izvestia that the U.S.S.R. never stopped using the Gregorian calendar.


 * The five and six - day weeks resulting in thirty - day months were grafted on to the Gregorian calendar - 360 days of work weeks and five or six public holidays outside making up the 365/366 day Gregorian year.  Dates such as August 31 prove this.   However, the White Russian armies in the 1920's (Orthodox) were not keen on the Bolshevik reform - and of course the Orthodox church still uses the Julian calendar.   Authorities in far - flung provinces were slow to make the change, so it's perfectly true that the U.S.S.R. was not wholly Gregorian till 1929. 156.61.250.250 (talk) 16:41, 14 February 2015 (UTC)


 * You're noting the difference between formal promulgation and practical implementation. I am quite, quite, quite sure that many people and communities in Italy, Poland, Spain and Portugal did not immediately switch to the Gregorian calendar on 15 October 1582, either.  There would have been resistance and delays in the British switchover in 1752, particularly in their overseas colonies.  Of course there will always be problems in implementing a change like this.  That would be true even today, let alone in the days before instant mass communication.  However, the main thing we need to focus on here is that Russia formally switched to the Gregorian in February 1918.  Details of the less-than-uniform implementation of that policy can appear if they're available, but in a lower profile location in the article.  --   Jack of Oz   [pleasantries]  19:15, 14 February 2015 (UTC)


 * Considering that an encyclopedia article must be concise to be useful to the intended audience, I think it's OK to just mention the formal start of a change that was successful, and reduce emphasis (or even ignore) changes that were formally promulgated but weren't accepted by the populace and were later repealed.


 * An example of a somewhat recent change that has been slow to be accepted by the populace (and some governments) is the elimination of Greenwich Mean Time. If you ask the scientific community, they'll tell you it was renamed universal time in the 1930s. If you ask for an exact definition of GMT, they'll tell you there isn't one. Jc3s5h (talk) 13:45, 15 February 2015 (UTC)


 * I think it's useful to tell readers about the Eternal calendar and the French Revolutionary calendar.  We mention the Decree of Canopus but that change never got off the ground at all.   Regarding Jack of Oz's edits, he's done something with curly brackets but what's inside them doesn't seem to appear at all (at least not in my browser).   Can you elucidate what's happening here?
 * Re Greenwich Mean Time, if you look inside the Astronomical Almanack (I haven't consulted it for some years mind) there's a note that astronomers do not use the term "Greenwich Mean Time" because it's ambiguous.  But astronomers are not lawyers.   Lawyers go back in time (the doctrine of legal precedent) and will happily tell you that Greenwich Mean Time is the same now as it was in 1971. 156.61.250.250 (talk) 14:33, 15 February 2015 (UTC)

Turkey and the Gregorian calendar
In 1917 the Gregorian calendar was adopted by Turkey (Ottoman Empire) but not the Christian era. The calendar agreed with the Gregorian calendar except on the number of the year. On Dec. 6, 1925 a decision was made by the Republic of Turkey to adopt the Christian era as well. — Preceding unsigned comment added by Ybgursey (talk • contribs) 17:31, 23 February 2015 (UTC)


 * See Adoption of the Gregorian calendar. 156.61.250.250 (talk) 09:55, 24 February 2015 (UTC)

Synthesis
I have reported this edit at WP:No original research/Noticeboard. Jc3s5h (talk) 15:49, 1 March 2015 (UTC)

7 months with 31 days, 4 with 30 and February's 28 (7x4) is an example of the GOD=7_4 algorithm/code
I added... The 7 months with 31 days, 4 with 30 and February's 28 (7x4) is an example of the GOD=7_4 algorithm/code.<ref http://GOD704.wikia.com</ref. For other patterns within the calendar consider Zeller's Congruence. 75.74.55.230 (talk) 05:13, 7 March 2015 (UTC)

An unnecessary split. Done without any discussion.
Why on earth did Dbachmann singlehandedly, without any discussion, split this article, remove nearly all info on the adoption of the G.C. and create this new article Adoption of the G. C. !? An uncalled for move AFAIC, done without any consultation.--Lubiesque (talk) 14:27, 24 January 2015 (UTC)


 * You should have weighed in at Requests for arbitration/Dbachmann. — Preceding unsigned comment added by 156.61.250.250 (talk) 13:13, 25 January 2015 (UTC)

See also Talk:Old Style and New Style dates (March 2015) -- PBS (talk) 09:26, 9 March 2015 (UTC)

Vernal equinox error
The "Accuracy" section is inaccurate. By definition, the position of the vernal equinox is arrived at after allowing for precession. The varying interval between astronomical vernal equinoxes is not caused by precession, it's caused by eastward movement of the perihelion relative to the stars. 156.61.250.250 (talk) 09:57, 10 March 2015 (UTC)

Using the Roman notation, the leap day is a.d. bis VI Kal. Mart. (24 February).
Is the sentence quoted above meaningful to anyone uninitiated to the arcana of the Roman calendar? If not, how does including it benefit the article? I will remove it. Rwflammang (talk) 00:25, 21 March 2015 (UTC)


 * Since you're arguing above that this is the leap day I would leave it, since it explains why. 87.81.147.76 (talk) 11:05, 21 March 2015 (UTC)


 * Let me heartily recommend removing both sentences from the article, since neither gives the article any benefit. Rwflammang (talk) 17:47, 21 March 2015 (UTC)


 * If Rwflammag just removes it, the article will say February 29 is the [one and only] leap day, which Rwflammag disagrees with. I do think the passage should be revised to say that currently, February 24 is the leap day in the Roman Catholic Church but February 29 for civil purposes, rather than saying it depends on whether the date is written in Latin or English. Jc3s5h (talk) 13:04, 21 March 2015 (UTC)

Archiving
This page is currently automatically archived, I believe after 60 days. Automatic archiving is ridiculous for the level of traffic here. People will start discussing the same topic over again because they haven't seen the discussion which has been moved into the archive. If there are no objections I'll revert it to manual. 87.81.147.76 (talk) 18:10, 22 March 2015 (UTC)


 * I do not agree with you. Manual archiving is a bad idea, particularly as there is bad faith editing on this talk page. The IP address you are using has only been active for three months and you have only made two comments to this page neither of which have been archived. I presume that you have your own reasons for using an single issue IP account, however while you are using an IP account, while they are not blocked, you are of course free to add comments to this page and to the article, you are not to alter the archiving of this page, although you can ask others to do if for you. -- PBS (talk) 08:08, 24 March 2015 (UTC)


 * I checked the numbers: there is a throughput of about 20k over the last year so I have altered the archiving out to 365 days, on current through put that will expand the size of the page to about 30k with about 17 sections. If it proves to be much larger (either in size of sections) then it can be altered. -- PBS (talk) 08:31, 24 March 2015 (UTC)

Which day is the leap day?
Is the leap day February 29 or February 25. In Roman terminology, February 24 was (and is) the sixth day before the kalends (beginning) of March. After the Julian reform, leap years were created by having two sixth day before the kalends of March, what we would call February 24 and 25. According to this article some Catholic feasts are observed according to their Roman nomanclature, as so-many days before the beginning of March, and seem to shift a day later when the modern method of counting from the beginning of the month is done.

On the other hand, secular dates that are set for the same date every year would occur on the date with the specified name, such as February 27, whether it was a leap year or not. But in the USA, I am not aware of any holidays or important national deadlines that are set for February 24 through February 28.

Another question is who is in charge? If the Catholic Church, Protestant churches, and the government all make their own choices, should we describe any one of the choices as the correct interpretation of the Gregorian calendar? Jc3s5h (talk) 14:47, 24 February 2015 (UTC)


 * I have found a source, Richards' 1998 book, which I have added to the list of references. Richards not only had his book published by Oxford university press, but also went on to write the "Calendars" chapter in the 3rd edition of the Explanatory Supplement to the Astronomical Almanac.


 * Richards (1998, pp. 100–101) indicates the leap day was inserted between 23 and 24 February, and named bis Kal. Mart while the Julian calendar was in effect and the practice was continued when the Gregorian calendar was adopted; the Roman Catholic Church was still using the practice when Richards wrote in 1998. The Anglican Church changed to regarding February 29 as the leap day in 1662, long before adopting the Gregorian calendar.


 * I would like to see a definitive source as to when the Roman Catholic Church changed to regarding 29 February as the added day, but have not been able to find one.


 * I believe the information should be in the article since the article covers both present and past usage of the calendar. Jc3s5h (talk) 14:54, 19 March 2015 (UTC)

Leap day is the bissextile day
The evidence presented for the leap day being the 29th of February is invalid. To see why, let's start with the Catholic evidence.

It is untrue that February dates after the 23rd have been cleared of commemorations as a cursory examination of the current Martyrologium Romanum will make clear. Look under 24 February, and you will see the rules for the bissextile day stated clearly, namely, that the day is inserted then. Furthermore, an examination of the Liturgia Horarum (on page 16 of, e.g., volume 2) shows that it clearly states that one dominical letter is used up to 24 February, and another after. While most of the saints in the Martyrology have days attached to the ordinal day of the month, not all do; four saints are assigned to pridie calendas martias, which is 29 Feb in bissextile years, and 28 Feb in other years.

It is untrue that counting days as ordinals of the month implies that the leap day is added to the end rather than inserted on sexto calendas martias. To illustrate this point, consider the 366th day of the year. It occurs only in leap years, and not in other years. So do we consider it the leap day? Ridiculous! In the same way, numbering the days in order does not mean that a day is inserted between pridie calendas martias and calendis martiis. Keying celebrations of saints days to the ordinal count, or not, tells us nothing about which day is inserted; that is simply the nature of ordinals.

I would like to see a definitive source as to when the Roman Catholic Church changed to regarding 29 February as the added day, but have not been able to find one. You never will find one, for one does not exist.

An article from the City Pulse is submitted as evidence. In it, a clueless journalist asks an equally clueless "calendar expert" about the evidence. To answer the question, does the expert whip out his Martyrology? His breviary? Any primary source whatsoever? Why no. He clicks on a website! He clicks on February 29th; it's blank. Therefore...

So much for the Catholic evidence. What about the Book of Common Prayer? What does it say? Why nothing at all. "It is implied..." quoth the footnote. In other words, the footnote author has original research to conclude that ordinals imply appending a day, rather than inserting a day, when ordinals imply nothing of the sort.

So the footnote is wrong and must be removed. What about the (now unsourced) statment which it is supporting? It also must be removed.

I'll get right on it. Rwflammang (talk) 00:18, 21 March 2015 (UTC)


 * I generally agree the information inserted by User:156.61.250.250, who is currently blocked, involves too much hand waving to satisfy me. However, when you (User:Rwflammang) reverted with no talk page discussion and terse edit summaries, I was left with the impression that you believed February 29 was the one and only leap day, ever since 1582.


 * There is at least one reliable source that states that both February 29 and February 24 (or perhaps February 25) has been used as the leap day at various times. Richards (1998, p. 100–101) states:
 * "In the Christian calendar, 29 February is the intercalcated day in leap years. Leap years were so called because, as was written in the 1604 edition of the Anglican prare book, 'On every fourth year, the Sunday Letter leapeth'. The years which are not leap years are generally called 'common' years...."
 * "There is a subtle difference between Anglican and Roman Catholic practices concerning the leap day. In the old Roman Julian calendar, that extra day was, as we have seen, inserted between the VII Kal. Mart. and the VI Kal. Mart.&mdash;that is, between 24 and 25 February. That practice was taken over by the Roman Catholic Church and continued by the English until 1662, when the extra day was moved to a place between 28 February and 1 March, and called 29 February. All this makes little discernible difference, except that in the Roman Catholic practice the Sunday, or dominical letter, is changed after 24 February rather than after 29 February. This can never affect the date of Easter but it does lead to celebrations of the feast of St. Matthias taking place on different dates in leap years in the two Churches."
 * As far as which is the intercalcated day for civil purposes, I think your reasoning for not considering the 366th day of the year to be the intercalcated day applies. American Independence day is celebrated on the 185th day of the year in common years, but 186th day of the year in leap years, so the intercalcated day must be before then. If we could find well-known public celebrations or deadlines in late February, and observe if they move or not, we could demonstrate which day is the civil intercalcated day. Or we could just take Richards' word for it. Jc3s5h (talk) 01:47, 21 March 2015 (UTC)


 * All of this information is a better fit for the leap day article. Here it clutters up this already over long article and distracts from its salient points. Rwflammang (talk) 17:52, 21 March 2015 (UTC)


 * It's ok to put the details in "Leap year" but the basic information about when the leap day occurs in this article, in part because it switched (for many purposes) from February 24 to February 29 around the same time the Gregorian calendar was adopted, so tends to be associated with the Gregorian calendar (although not a formal part of the change). Jc3s5h (talk) 12:33, 25 March 2015 (UTC)

Difference between Julian and Gregorian dates
In the third century the difference was zero. Thus H-(H/4)-2=2-[2/4]-2=2-0-2=0. In these equations the square brackets [ ... ] denote integer division.

In the second century the difference is -1. Thus 1-[1/4]-2=1-0-2=-1.

In the first century the difference is -2. Thus 0-[0/4]-2=0-0-2=-2.

In the first century BC the difference is -2. Thus -1-[-1/4]-2=-1-(-1)-2=-2.

In the second century BC the difference is -3. Thus -2-[-2/4]-2=-2-(-1)-2=-3.

In the third century BC the difference is -4. Thus -3-[-3/4]-2=-3-(-1)-2=-4.

In the fourth century BC the difference is -5. Thus -4-[-4/4]-2=-4-(-1)-2=-5.

In the fifth century BC the difference is -5. Thus -5-[-5/4]-2=-5-(-2)-2=-5.

So the section was correct as written. You should put it back the way it was. 156.61.250.250 (talk) 13:10, 10 May 2015 (UTC)


 * It is perhaps less confusing if the mathematically equivalent relation D = floor(y/100) - floor(y/400) - 2 is used. Here y denotes the year and 'floor' denotes the floor or entier function. AstroLynx (talk) 13:50, 10 May 2015 (UTC)

The floor function gives a different result than truncation for negative numbers. I think it's better to use a relationship from a reliable source, so if the article is vandalized, an editor who does not want to rederive and retest the relationship can just restore the relationship from the cited source.

Let us postpone consideration of edge cases, after we agree on a correct formula for mid-century.

In the following table AYN means astronomical year numbering. The years assigned to centuries is common in offical sources but the Oxford English Dictionary said 2000 was the first year of the 3rd millenium. In ranges, the word "to" is inclusive, that is, "1 to 100" means 1 January AD 1 through 31 December AD 100. "Computed Secular Difference" is using the formula in the article [D = H - (H/4) -2, truncating division] which agrees with Blackburn and Holford-Strevens, using the value of H for mid-century to avoid edge cases (AD 250, AD 150, ... -550 BC).

The "Calendrica Secular Difference" was computed using the Calendrica LISP program provided by Cambridge University Press for use with Dershowitz and Reingold's book. Calendrica was used to convert Gregorian June 15 of the mid-century year to Julian and the difference is tabulated.

Jc3s5h (talk) 15:05, 10 May 2015 (UTC)

Gregorian calendar - numerical method text uses unreliable source
See User_talk:JoeSperrazza. JoeSperrazza (talk) 04:22, 11 August 2015 (UTC)


 * P.S. A formatting error occurred whenever I pasted the comment made at User_talk:JoeSperrazza into this section of the article talk page. Thus, I posted it to my talk page. Discussion would be better here, however. JoeSperrazza (talk) 14:19, 11 August 2015 (UTC)

North Korea Calendar?
There is no reference to the North Korean Calendar in the infobox. 120.151.205.179 (talk) 10:13, 18 August 2015 (UTC)
 * It's under Juche calendar. If you have any other issues with the infobox go take it up on the box's talk page. Arcorann (talk) 06:45, 21 August 2015 (UTC)

Julian calendar
Julian calendar was a kind of ancient Occidental solar calender is that right? SA 13 Bro (talk) 22:46, 14 September 2015 (UTC)


 * Sort of. It was ordered by Julius Caesar, so it is western and ancient. And it is solar. But it was still in use in Greece as an official government calendar until 1923, and it is still used by some branches of the Orthodox Church. So it is also modern. Jc3s5h (talk) 23:07, 14 September 2015 (UTC)


 * That was the GREAT men! The ancient kind of solar calender is still using at the modern time... SA 13 Bro (talk) 23:22, 14 September 2015 (UTC)

Semi-protected edit request on 31 December 2015
the text says that Eatern Orthodox churches are using the old calendar but Romania and Bulgaria are orthodox but use the gregorian calendar

86.171.147.61 (talk) 18:04, 31 December 2015 (UTC)


 * Red question icon with gradient background.svg Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format. Datbubblegumdoe[talk – contribs] 02:49, 7 January 2016 (UTC)

England and Jan 1
The article is unclear or misleading about England's shift to "New Style Julian". It states that the change to January 1st was made (officially) in 1752, but that January 1st was regarded informally as New Year's Day, and gives an example from Samuel Pepys. So far, so good. It is left open just how far people thought of the year as starting in January, but the implication is that the January start was just an informal concept.

However, year-start on January 1st was in fact in formal (if not "official") written and printed usage in England before 1752. For example, in the London Newspaper The General Advertiser, issue number 4114 was dated Thursday December 31, 1747, and issue number 4115 was dated Friday January 1, 1748.

How general, and when, was public adoption of "New Style Julian?". Were the newspapers really living in different years from officialdom for nearly three months of every year? Could a knowledgeable contributor please clarify the article on this? Wyresider (talk) 23:43, 19 January 2016 (UTC)

External links modified
Hello fellow Wikipedians,

I have just added archive links to 1 one external link on Gregorian calendar. Please take a moment to review my edit. If necessary, add after the link to keep me from modifying it. Alternatively, you can add to keep me off the page altogether. I made the following changes:
 * Added archive https://web.archive.org/20060211015021/http://ata-spd.org:80/Informate/Intercambios/InterV9No1Mar05.pdf to http://www.ata-spd.org/Informate/Intercambios/InterV9No1Mar05.pdf

When you have finished reviewing my changes, please set the checked parameter below to true to let others know.

Cheers.—cyberbot II  Talk to my owner :Online 10:34, 28 January 2016 (UTC)

Reference cleanup and restructuring?
Please review this recent edit. The purpose is to have more consistent formatting, and to add links between footnotes and references. The mechanism was to add templates where they previously weren't used (though attempting not to change the visual presentation, where the presentation was already consistent). Jc3s5h correctly asserts that changing to templates unilaterally is contrary to WP:CITEVAR. Is there a consensus for or against this change?

(Note that there are also corrections and expansions to some of the citations mixed into this change. That's a separate issue.)

Nitpicking polish (talk) 18:35, 24 February 2016 (UTC)


 * Back when these citations were first cleaned up and put in the present format, I would have strongly opposed using citation templates. They had some horrible problems, like not being able to put too many citations on the page or else some of them wouldn't be rendered. The citation templates are better than they were, although I think there is a bit too much error checking. For example, putting February 29 for years that were leap years in the Julian calendar but not the Gregorian (like 1700) creates error messages. I'll go along with whatever consensus other editors come to. Jc3s5h (talk) 20:54, 24 February 2016 (UTC)

Inter Gravissimas (W. Spenser & R. T. Crowley, Trans.) paywalled. Is there an open source of this translation?
This is paywalled:


 * Gregory XIII. (2002 [1582]). Inter Gravissimas (W. Spenser & R. T. Crowley, Trans.). International Organization for Standardization.

Is there another source for this translation of Inter Gravissimas?

--Geremia (talk) 20:41, 21 March 2016 (UTC)

Astronomers are subject to WP:RS and WP:V the same as anybody else
Jc3s5h has added a claim which, apart from making the nonsense statement that the vernal equinox is a certain number of days apart cites a source which gives the alleged separation to six places of decimals. This is unverifiable. It is said to relate to "near 2000" but a check cannot be made because how near is not specified. In some contexts 1900 might be "near 2000", in others 1995 might be rather far away. 77.98.244.158 (talk) 22:57, 28 March 2016 (UTC)


 * Are you claiming that Meeus and Savoie (1992), p. 42 is not a reliable source?   D b f i r s   19:46, 4 April 2016 (UTC)


 * It's a question of verification.  You've conspicuously failed to verify those six - figure decimal values. 77.98.244.158 (talk) 20:26, 4 April 2016 (UTC)


 * I don't need to personally verify them, just to cite them from a WP:reliable source.  "Jean Meeus explores the frequency of blue moons, planetary groupings, and a  great deal more, as only this master of astronomical calculations could."    D b f i r s   20:42, 4 April 2016 (UTC)


 * What a joke.  What have blue moons and planetary alignments have to do with the theory behind the calendar? 77.98.244.158 (talk) 20:53, 4 April 2016 (UTC)


 * Read the second half of the cite.   D b f i r s   07:09, 5 April 2016 (UTC)


 * The cite contains 23 words.  So the second half of it is "a great deal more, as only this master of astronomical calculations could".   Are you Jan Meeus' PR agent?   How does that verify a time - dependent algorithm, for which no time argument is given, to six places of decimals?   At 15:07, 10 May 2015 you said

The values for the equinox and solstice years were presumably calculated by the same method, but using the true longitude instead of the mean longitude.

I get the distinct impression that you don't have the faintest idea what you are talking about. 77.98.244.158 (talk) 12:23, 5 April 2016 (UTC)


 * I agree that neither of us has been able to find the methodology used by Jean Meeus (of whom I had never heard until you objected to his research), but his figures seem to be a modification of the formula derived by Jacques Laskar for the mean tropical year, or of one of the more recent equivalents. He gives a time argument (J2000) for the figure cited.    D b f i r s   13:05, 5 April 2016 (UTC)

Mean Solar Days
The current value of the tropical year is about 365.242181 mean solar days (please note that these are slightly different from ephemeris days). By my calculation, this makes the Gregorian calendar accurate to one day in about 3135 years. Have I miscalculated, or are other people comparing apples with pears? The estimation is slightly suspect, of course, because the length of the mean solar day changes slightly over time, but I don't see how the figure in the article is arrived at unless someone is using inappropriate rounding.  D b f i r s   07:45, 6 October 2016 (UTC)


 * I found that the value in the article, 1 day per 3327 years was substantially introduced in this 2005 edit by an editor who does not appear to be active. It was changed from 3300 years to 3327 years by an IP editor recently. I cannot reproduce this value.


 * I also cannot reproduce Dbfirs' value of 365.242181 mean solar days for the tropical year. Richards (p. 587) gives a value of 365.24217 mean solar days per year, or 365.24219 days if the day is 86,400 SI seconds. This is for 2000, but the formula on page 586 shows the change from 2000 to 2016 is negligible. When I use the value of 365.24217 mean solar days per year, and divide by the tropical year when calculating the error, I get an error of 1 day per 3030 years. Jc3s5h (talk) 13:55, 6 October 2016 (UTC)

References

Richards, E. G. (2013) "Calendars" in S. E. Urban and P. K. Seidelmann Explanatory Supplement to the Astronomical Almanac (3rd ed.). Mill Valley CA: University Science Books. ISBN 978-1-891389-85-0


 * I must admit that I copied the value from the lead in our article Tropical year and not from an academic reference. Perhaps this article needs changing?  Using Richards' value, I agree with your 3030 years.  Would you like to make the appropriate changes?    D b f i r s   07:30, 7 October 2016 (UTC)


 * OK. I'll have a look at "Tropical year'' too. Good catches. Jc3s5h (talk) 13:45, 7 October 2016 (UTC)


 * Thank you for updating the values.   D b f i r s   15:56, 7 October 2016 (UTC)

North Korean Calendar?
In the infobox there is no reference to the North Korean Calendar. PLEASE ADD! 120.151.205.179 (talk) 10:13, 18 August 2015 (UTC)
 * Yes, it is, under "Juche calendar". --John Maynard Friedman (talk) 19:30, 17 December 2016 (UTC)

Semi-protected edit request on 21 December 2016
In the table 'Adoption of Gregorian Calendar', please add Poland/Lithuania. Below part of the code changed to corrected form. Source? Wikipedia in the same paragraph, a few lines above the table. Astymo (talk) 23:06, 21 December 2016 (UTC)
 * Thank you for your contribution. Unfortunately the text a few lines up is unsourced, so I've tagged it and thus your reasonable request will have to wait until evidence is produced. [By the way, one of our fundamental principles is that Wikipedia must never cite itself. That way madness lies. --John Maynard Friedman (talk) 00:41, 22 December 2016 (UTC)

Ok. Understood. So please see below few links to confirm information about Adoption of Gregorian calendar in Poland-Lithuania, as one of the first states. I hope it will be enough. http://www.webexhibits.org/calendars/year-countries.html https://www.timeanddate.com/calendar/julian-gregorian-switch.html http://www.messagetoeagle.com/the-gregorian-calendar-implemented-on-oct-5-1582/ http://www.almanac.com/fact/first-day-of-conversion-to-gregorian-calendar — Preceding unsigned comment added by Astymo (talk • contribs) 21:07, 3 February 2017 (UTC)
 * Yes check.svg Done Stickee (talk) 00:13, 2 March 2017 (UTC)

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Block quote in lead
In this edit in which Future Perfect at Sunrise restored the correct version of the quote in the lead, the edit summary was "rv, this is what the source actually says (but as an aside, it would be preferable not to use a literal blockquote at all here".

Here is the quote: "Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. For example, the years 1700, 1800, and 1900 are not leap years, but the year 2000 is."

Personally, I think the lead would flow better if it weren't a block quote. But this statement is possibly the most important thing Wikipedia has to say about the Gregorian calendar, and editors are constantly tinkering with it. Often, the tinkering is wrong. That's why I think making it match a reliable source is more important than how well the lead flows. Jc3s5h (talk) 12:11, 16 May 2017 (UTC)

Semi-protected edit request on 5 September 2017
Please revise the link in note 3 from the current line below... The calendar was a refinement to the Julian calendar See Wikisource English translation of the (Latin) 1582 papal bull Inter gravissimas ...to the revised line below... The calendar was a refinement to the Julian calendar See Wikisource English translation of the (Latin) 1582 papal bull Inter gravissimas

Regards 96.229.223.56 (talk) 16:47, 5 September 2017 (UTC)


 * Done. Thanks for reporting it. Jc3s5h (talk) 17:02, 5 September 2017 (UTC)

Pattie footnote
The footnote saying "mobs rioted at the time of adoption, crying 'Give us back our eleven days'." is very likely to be completely incorrect (unless this Pattie person somehow found a historical source that was overlooked by all other scholars, and other scholars in turn ignored Pattie). The only real valid source that careful scholars have been able to find is File:William Hogarth 028.jpg / File:An Election Entertainment.jpg, a 1755 painting of the 1754 Oxfordshire elections (two years after the calendar change), where there's a "Give us our eleven days" campaign banner. Vague unsourced reports of 1752 calendar riots are found in a number of accounts published long after 1752, but those historians who have gone looking for evidence for them in contemporary 1752 newspapers and such haven't found support for this. I think this article should avoid making startling claims about the adoption of the Gregorian calendar which are rejected in the Wikipedia "Adoption of the Gregorian calendar" and "Calendar (New Style) Act 1750" articles. Churchh (talk) 09:25, 7 October 2017 (UTC)
 * It has always been the case that an attractive and well-presented story can be halfway round the world before Truth has packed his suitcase (with apologies to Super Mac or whoever it was).  I remember reading the same "story" - here attributed to T.S.Pattie - in another author's A-level school text book around the same time that Pattie was writing his book.   Since the "story" is widely reported and repeated, you cannot simply ignore it here, either under wiki "rules" or in terms of basic common sense, but you certainly can improve the text to make clear that other versions exist, and that the "story" is short on plausible pedigree, if that is what you believe.  And if you have heavyweight sources you can do so persuasively.   Please feel free...    Success Charles01 (talk) 09:55, 7 October 2017 (UTC)


 * Robert Poole, "Give Us Our Eleven Days: Calendar Reform in Eighteenth-Century England", Past and Present, nr. 149 (1995), 95-139, gives the full story of the origin and subsequent popularity of this well-known calendar myth. AstroLynx (talk) 12:02, 7 October 2017 (UTC)

For the present, I have just commented out that footnote, with a view to removing it unless someone comes forward to defend it. Otherwise, the case is a good one that we ought to have a sentence or two putting this myth to bed. Could someone (AstroLynx, since you have Poole's book) do the needful? --John Maynard Friedman (talk) 16:39, 8 October 2017 (UTC)

Edit request adoption by Yugoslavia
Please add a note in the list of adoption dates by countries: Currently it states that Yugoslavia adopted the Gregorian calendar in 1919. A note should be added that this was only in the regions comprising the former Kingdoms of Serbia and Montenegro (present-day Kosovo, Montenegro, Serbia and Macedonia). The western and northern regions were already using the Gregorian calendar. For example, most of Slovenia adopted the Gregorian calendar at the same time as Austria in 1583. Coastal Croatia which was at the time ruled by Venice adopted the Gregorian calendar in 1582, while continental Croatia ruled by the Habsburgs adopted it in 1587 along with Hungary. The Gregorian calendar was used in Bosnia and Hercegovina since the 16th century by the Catholics, and was formally adopted for government use in 1878 following occupation by Austria-Hungary. -- 180.149.192.132 04:37, 29 September 2017‎ ‎.
 * Done. Please review. --John Maynard Friedman (talk) 19:36, 30 September 2017 (UTC)
 * Thank you. Much appreciated. — Preceding unsigned comment added by 180.149.192.132 (talk) 01:29, 10 October 2017 (UTC)

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Common era calendar
With this edit User:Ounbbl added to the lead: In view of its global use in different religions, languages, and traditions, proposed is the term 'Common Era Calendar' which is neutral and more appropriate than the traditional term 'Gregorian'. Unsurprisingly, User:Dbfirs reverted, saying that is unsourced. He/she might also have said that the lead summarises the body and there is nothing about a common era calendar in the body. But there should be, while keeping in mind WP:UNDUE (since there is a lot less evidence for its use, unlike CE/BCE).

First, here are some citations (using Google Books to get to the specific usage]:
 * Proving It - Eschatology That Makes Sense in Four Research Reports By Robert Wright
 * Religious Celebrations: An Encyclopedia of Holidays, Festivals ..., Volume 1 By J. Gordon Melton
 * A Complete Guide to Sikhism By Jagraj Singh

I suggest we have a short section at the end that acknowledges that an alternative name exists. I don't see how we can provide evidence for the extent or otherwise of its usage, but then again how often do you even see the qualifier "Gregorian" used? --John Maynard Friedman (talk) 12:23, 22 November 2017 (UTC)

I've seen it used by Peter Meyer in his website [| Hermetic Systems: Calendar Studies] and thought the term was invented by him. Karl (talk) 12:47, 22 November 2017 (UTC)


 * I must admit that I had never heard the term used in this way, but if it has significant usage (other than the inventor's website) then I'm happy to have a paragraph added. The references seem to be more about the use of CE and BCE than about the leap-year system named after Gregory.    D b f i r s   14:16, 22 November 2017 (UTC)


 * I think it's safe to say no one in the English-speaking world has the practical authority to pronounce a new name for a calendar by fiat. Anybody can coin a phrase and wait to see if it catches on. No one in this discussion has put forward a definition in a reliable dictionary, encyclopedia, or the like, so it's hard to say if "Common Era calendar" has caught on or not. Also, lacking such a source, we can't be sure of what the definition is. Does it always mean Gregorian calendar? Could it also mean Julian calendar in places and times where that was in effect? Jc3s5h (talk) 17:03, 22 November 2017 (UTC)

The day in about 3000 years
Hello everyone. Such als widely is known about every 3100 years a leap year must be changed in a common year. See the table on http://www.truebiblecode.com/BLCTable.html Hereby follows a short track of this table (each 400 years). Please note: ONLY the (before 1582 fictieve) Gregorian calendar is used in this table. The year 0 does NOT exist in this table, so that 400 years before 0300 AD is 0101 BC instead of 0100 BC, so that there is a shift of 1 day!

Vernal equinox 2101 BC 21 March 13:37 1701 BC 21 March 08:02 1301 BC 21 March 02:50 0901 BC 20 March 22:04 0501 BC 20 March 17:45 0101 BC 20 March 13:54 0300 AD 21 March 10:31 0700 AD 21 March 07:38 1100 AD 21 March 05:13 1500 AD 21 March 03:16 1900 AD 21 March 01:45 2300 AD 21 March 00:38 2700 AD 20 March 23:53 3100 AD 20 March 23:27

It seems that a good proposal would be that every 3200 year will be a common year instead of a leap year, to keep the vernal equinox on 21 March. Thus 3200, 6400 en 9600 would then be all three common years instead of leap years. But see the figure on https://de.wikipedia.org/wiki/Gregorianischer_Kalender#/media/File:TropicalAndGregorianYear_MeanSolarDays.png If the Gregorian calendar would be introduced in 6000 BC and there was an additionad rule too that from then after every 4800 year a century year would be a common year instead of a leap year, that then the length of the mean(!) Gregorian year then would be lasts about 365,24228 days. But from 8000 AD every 800 years would then be a common year instead of a leap year and so on, thus the Gregorian year from then would be lasts about 365,24128 days, thus 0,001 days shorter! 84.80.54.162 (talk) 15:58, 28 March 2018 (UTC) — Preceding unsigned comment added by 84.80.54.162 (talk) 18:14, 26 March 2018 (UTC)


 * There have been lots of proposals, but none have been implemented because we don't yet know what will happen to the length of the day a thousand years hence, or whether we will care about the date of the vernal equinox or even use earth-based calendars in a thousand years' time.  Dbfirs  19:36, 26 March 2018 (UTC)


 * Regardless of the merits of this - or any other - proposal, this talk page is NOT the place to be advocating for it. This page is for discussion of improvements to the Wikipedia article on the Gregorian Calendar.  --   Jack of Oz   [pleasantries]  19:57, 26 March 2018 (UTC)

WP:SYN Non-sequitur
Lilius's proposals had two components. Firstly, he proposed a correction to the length of the year. The mean tropical year is 365.24219 days long.[21] As the average length of a Julian year is 365.25 days, the Julian year is almost 11 minutes longer than the mean tropical year.

[21] is a modern reference. Lilius had no idea of this estimate. His idea of the length of the tropical year was actually pretty wrong; see Moyer Sci. Am. 1982. — Preceding unsigned comment added by 86.126.3.203 (talk) 22:58, 29 August 2018 (UTC)


 * I added a sentence giving a widely used value for the length of the mean tropical year in Lilius's time, with a citation to another work of Moyer. Jc3s5h (talk) 00:10, 30 August 2018 (UTC)

To deal with the 10 days of accumulated drift...
The lead currently describes how the calendar was 'jumped' to "deal with the 10 days of accumulated drift". But I can't see where we explain what it drifted from. Was it Nicea (325)? Or their assumed date of the crucifixion? Anyone? --John Maynard Friedman (talk) 16:28, 27 October 2018 (UTC)


 * It's explained later, in the "Background" section:
 * "The Church of Alexandria celebrated Easter on the Sunday after the 14th day of the moon (computed using the Metonic cycle) that falls on or after the vernal equinox, which they placed on 21 March."


 * The method of computing the date of Easter used by the Church of Alexandria eventually spread throughout Christendom (until the agreement was disturbed by the introduction of the Gregorian calendar). Liturgically, the spring equinox is considered to be on March 21, but by the 1500s it was occurring around March 11.
 * It would be challenging to explain all that in the lead. Jc3s5h (talk) 17:00, 27 October 2018 (UTC)
 * D'oh!. I was being particularly dim. I searched down the article for a simple explanation and it was right there in the preceding sentence "to stop the drift of the calendar with respect to the equinoxes". Thank you for your patience. --John Maynard Friedman (talk) 17:10, 27 October 2018 (UTC)

I have changed the wording to make it a little clearer [IMO] without getting bogged down in the lead about the Jewish Calendar, Passover, and all that. Revert if you disagree. --John Maynard Friedman (talk) 18:48, 27 October 2018 (UTC)

Tuscany
This article seems to state that Tuscany adopted the Gregorian calendar already in 1582, but the start of the year was changed to January 1 only in 1750. Burzuchius (talk) 09:06, 27 October 2018 (UTC)
 * Google Translate has its limitations but as far as I can tell, that document is aimed at the general lay reader and [being charitable] chose not to get bogged down in details about the change of start of year [which happened in different countries at different times, sometimes independently of the Julian/Gregorian change (as in Scotland) and sometimes concurrently (as in England). In any case, surely it is outside Wikipedia's jurisdiction? Or am I misunderstanding your point? BTW, someone should get a hammer and chisel out and carve "citation needed" onto that stone tablet! :) --John Maynard Friedman (talk) 16:00, 27 October 2018 (UTC)
 * Corrected. Burzuchius (talk) 17:47, 19 November 2018 (UTC)

Difference from the Julian calendar
How could the difference between the Julian and the Gregorian calendars be only 10 days when the Gregorian calendar was introduced in 1582?

Mathmatically, the difference should have been 12 days as the difference between the two calendars increases with one day per century year which is not a leap year (years which are not multiples of 400) and though until 1500, it had passed 12 century years which would not have been leap years: 100, 200, 300, 500, 600, 700, 900, 1000, 1100, 1300, 1400, 1500. But even though the difference mathmatically should have been 12 days, it was only 10 days, can someone explain why? 90.226.9.16 (talk) 22:40, 7 September 2018 (UTC)


 * The goal of the Gregorian calendar reform was to return the date of the vernal equinox to what it was at the time of the First Council of Nicaea in 325. It was never the goal to set it to what it was in about 33, the approximate year Christians believe the Resurrection of Jesus occurred.
 * Dionysius Exiguus' Easter table, created in 525, and other tables following the same principles, were used throughout Christendom by the time of the calendar form, and those tables treated March 21 as the equinox. Jc3s5h (talk) 23:13, 7 September 2018 (UTC)
 * Since the Gregorian calendar (1582) was set to 325AD there are nine centuries that lost a day over that 1257 year period (500, 600, 700, 900, 1000, 1100, 1300, 1400, 1500) so there's a discrepancy - but it's an extra day removed not two days added. I assume that the only plausible solution is that 300 AD lost a day too, making the 4th Century (and therefore the 1st Council of Nicaea) conform to the new calendar. 119.224.77.162 (talk) 21:11, 2 November 2018 (UTC)
 * You give too much credit! Far more likely is this: "we observed that 21 March did not coincide with the equinox, as Canon Law expects. Therefore we have to move the calendar by as many days as it takes so that it does. End of." --John Maynard Friedman (talk) 19:31, 3 November 2018 (UTC)
 * "End of" indeed. I'll take it that as it's the interface between science and the church we're talking about; when confronted by anomaly that can't be readily explained, then ... just pretend we didn't hear the question while we shuffle the deck of cards. That works for me. Thanks for clearing that up John Maynard Friedman :) 119.224.77.162 (talk) 09:20, 14 December 2018 (UTC)

Year of Our Lord fond of Gregorian calendar?
CE AD anyone? 124.106.137.103 (talk) —Preceding undated comment added 00:49, 14 November 2017 (UTC)


 * Yes, please. I'll have 2016.9 of them.  I'm not concerned about what pair of letters they come with because they have the same length whichever label you attach.    D b f i r s   08:27, 26 November 2017 (UTC)


 * AD stood for Anno Domini, usually translated as "In the year of Our Lord ...", which amounts to religious fanatics flaunting their ignorance of even the scantily documented events they pretend were miraculous. "CE" works pretty well, bcz they can claim it means the same as AD, even tho CE simply means "Common[ly used] Era" to most of the world, who either are offended by Christian exceptionalism, or just don't give a FF@aRD about it.  Jerzy•t 21:42, 2 January 2019 (UTC)

Edit by John Maynard Friedman
I have reverted this edit by John Maynard Friedman for the following reasons:


 * 1) Going against WP:CITEVAR it introduces citation template to an article that generally doesn't use them (although editors ignorant of, or who scoff at WP:CITEVAR]] might have snuck a few in).
 * 2) " is a calendar that is widely around the world". Um, widely WHAT?
 * 3) "The international standard for the representation of dates and times, ISO 8601, uses the Gregorian calendar." No, ISO 8601 is not THE international standard for the representation of dates and times. It is used only lightly in Europe, Australia, and North America, and even the ISO has several other date and/or time standards to pick from, not to mention other standards organizations, as well as numerous style and usage guides.

Perhaps it would be beneficial to discuss what is wrong with the version before the change before making changes. Jc3s5h (talk) 22:09, 22 March 2019 (UTC)
 * WP:LEADCITE says there should be no cites in the lead anyway but no matter, let's stick to the important stuff. The article gives two citations in support of the assertion that the Gregorian Calendar is the one most widely used around the world. Neither citation does so. The US Naval Observatory says The civil calendar in use around the world (Gregorian calendar) is a solar calendar.  L. E Doggett says only that The Gregorian calendar today serves as an international standard for civil use.  So the text as it stands is invalid and had to be changed. I will now go back and tag it, inviting you to provide the evidence or delete the statement. --John Maynard Friedman (talk) 23:18, 22 March 2019 (UTC)
 * I haven't been able to find a source that says, in so many words, that the Gregorian calendar is the one most widely used around the world for civil use. Richards (2013, p.) implies it.
 * "According to a recent estimate (Fraser 1987), there are about forty calendars in use in the world today and more than that have been abandoned. This chapter is concerned with only a few of these. We discuss here nine. The first of these is the Gregorian calendar, which is now used throughout the world for secular purposes.... We discuss a further six...which are in current use to determine the dates of religious or cultural activities. We discuss two more...which are of historical interest."


 * So after consulting a survey that lists at least 40 calendars, Richards considers the Gregorian calendar the only one worth describing for secular purposes.
 * My concern is that if we don't say it is the most popular for civil use, a reader unfamiliar with the word "Gregorian" may left wondering if the calendar they use every day, which has the same structure described in the article, is the Gregorian calendar or something else. Jc3s5h (talk) 23:53, 22 March 2019 (UTC)
 * Am I understanding this disagreement correctly? The article used to say "The Gregorian calendar is the most widely used civil calendar in the world." with a reliable source that above we are told says "The civil calendar in use around the world (Gregorian calendar) is a solar calendar." Of course that source verifies the original text. What is the problem with it? At any rate, the suggestion that readers should be told that the Gregorian calendar is just another calendar is very inappropriate. Johnuniq (talk) 23:59, 22 March 2019 (UTC)
 * In these edits I have added a source by Dershowitz and Reingold, published by Cambridge University Press. Perhaps John Maynard Friedman will remove the template indicating the information is not in the cited source. Jc3s5h (talk) 00:29, 23 March 2019 (UTC)
 * With very little OR, we can observe that this Calendar is the [only] civil calendar used in North and South America, Europe, Sub-Saharan Africa, India/Pakistan, China and Japan – and thus by the very large majority of the world's population (or at least its administrators).  So I have no doubt whatever that it is the calendar most widely used. But here is the problem: none of the sources (including the new one) say that. They only say that it is widely used. Great assertions need great evidence and the most is one such. So we need a form of words that recognises its great importance but avoids using the M word. Which is where I came in and, I admit, made a dog's breakfast of it. --John Maynard Friedman (talk) 17:28, 23 March 2019 (UTC)

New opening sentence
I have changed the opening sentence so that it says 'the calendar used in most of the world', which is exactly as cited and observably true. ('The calendar most used in the world' was always going to be a struggle to cite since it is very difficult to prove). As usual, WP:BRD. --John Maynard Friedman (talk) 21:25, 31 March 2019 (UTC)

Change footnote style to use 'template:efn' instead of 'ref group=Note' ?
IMO, the ref group=Note method of footnoting creates a footnote style that is ugly and intrusive like this,Note 10 breaking the flow of the eye along the line and demanding the reader's attention. Template:efn, on the other hand, creates an unobtrusive single letter superscript like this,x which is much easier on the eye and gently invites readers to note that further details are available should they want them.

Comments? --John Maynard Friedman (talk) 21:43, 31 March 2019 (UTC)


 * I think the change would be acceptable.
 * If you want to work on the citations, I notice that some short citations call out a source in the bibliography (which is called "References" while others give all the details of the publication right in the footnote. It appears the short citations are mostly to books, and the full citations are mostly journals and web pages, but this pattern is not consistent. Jc3s5h (talk) 22:06, 31 March 2019 (UTC)
 * Yes, for example ref 5 just says 'Blegen n.d.' because, although the book is listed under References [sb Sources] it has not been given the full cite book treatment with ref=harv. So I shall have to use this style of book citation, unless you object strongly? --John Maynard Friedman (talk) 13:29, 1 April 2019 (UTC)
 * (The popup will be inline. Simply highlighting the line is a 'feature' where reference and target are close. Which will not be true). --John Maynard Friedman (talk) 13:36, 1 April 2019 (UTC)
 * Although $[Note 10]$ can be shortened to $[n 10]$ by using group=n, I prefer efn-ua (explanatory foot note - upper alpha) because the resulting upper case letter $[J]$ is the same vertical size as a ref number $[10]$ and cannot be confused with the multiple lower case letters prefixing the citation itself ($^ a b c d e f$) which refer to the multiple inline numbers. Regarding citations I have no preference, but note that if facts are on many different pages in a single book, a problem occurs. I prefer an inline rp (reference page) immediately after the reference marker itself, adding the page to it, $[10]:15$ for page 15 in ref 10. This avoids the need for a separate References section. However, Gregorian calendar already has an extensive References section so it doesn't really help, leaving the use of a shortened footnote sfn. — Joe Kress (talk) 18:41, 1 April 2019 (UTC)
 * The citation system adopted for this article is similar to what one might find in a paper journal. There is no link between the short citation and the full information in the "References" section. Changing all the citations in the article to use citation templates would go against WP:CITEVAR unless there is consensus for the change on the talk page. It would be best to start a new thread with an appropriate heading so people who might be interested will see it on their watchlist. Jc3s5h (talk) 15:43, 1 April 2019 (UTC)
 * I've seen some people complain that the page numbers produced by rp are ugly; I think they're a little jarring but not too bad. Sometimes it may be necessary to describe a location that is not a page, such as "Chapter 3" or "inside front cover". These would be rather distracting in running text. Jc3s5h (talk) 19:03, 1 April 2019 (UTC)
 * template:sfn, which is what is used to call out the citation, includes loc= (e.g., chapter, frontispiece, dust jacket, whatever you like, like this), as well as page=n or page=n–m. --John Maynard Friedman (talk) 20:06, 1 April 2019 (UTC)
 * If template:cite book with ref=harv is accepted, the effect will be much the same as at present, but with an optional extra. If you mouse over reference 5 as above, a popup containing 'Blegen n.d.' will still pop-up. The extra goody is that 'Blegen n.d.' will be an active link: if you choose to mouse-over it, then the full book citation will pop-up. NB that I am not proposing inline Harvard references, like this.(Einstein, 1907) – these have their place in academic papers but not in an encyclopedia. Does that resolve the concern? (I haven't looked at simple web citations, I propose to start with the books and see how it goes).--John Maynard Friedman (talk) 20:06, 1 April 2019 (UTC)

Can we stop the discussion about citations in this section please and continue in the new section following.

Coming back to Joe Kress's comment, I understand the concern but are there any examples of 'multiple lower case letters prefixing the citation itself ($^ a b c d e f$)' in this article? If they haven't happened before now, they are unlikely to do so as the article is very mature. --John Maynard Friedman (talk) 20:40, 1 April 2019 (UTC)
 * They do indeed occur multiple times in the second column of Citations. — Joe Kress (talk) 20:50, 1 April 2019 (UTC)
 * Rats, that'll teach me to do a proper check rather than a quick scan. --John Maynard Friedman (talk) 21:48, 1 April 2019 (UTC)

Which citation style to use?
The preceding section began as just about explanatory notes but has strayed into citation styles. This section is just about citation styles.


 * I would suggest each source be listed in alphabetical order in the "References" section with the appropriate Citation Style 1 template: books with cite book, journals with cite journal, web sites with cite web, and so on. In the case where a book or journal can be read on a web site, use cite book or cite journal respectively; include the url with url. Save cite web for sources that are purely web cites. Put ref=harv (or equivalent) in each citation, and use sfn for each footnote. Jc3s5h (talk) 21:03, 1 April 2019 (UTC)

Book citations
I propose that we use template:cite book with ref=harv, as described above. --John Maynard Friedman (talk) 20:35, 1 April 2019 (UTC)

Web citations
I prefer template:cite web, if only because it provides a check-list of what should be given. But other than that, I have no preference. --John Maynard Friedman (talk) 20:35, 1 April 2019 (UTC)
 * Per Jc3s5h, I should clarify that this cite web is for material that does not fit another category (like cite news, cite journal etc. If the material can be found on the web, then the url= function is used within the citation). --John Maynard Friedman (talk) 21:46, 1 April 2019 (UTC)

Semi-protected edit request on 23 April 2019
The last paragraph of section "Preparation" and the third paragraph of "Adoption" are essentially duplicates. They use the same duplicate source and can easily be merged. The second occurrence should be removed and the first changed to include the little information exclusive to the second (Antonio Lilio's brother Luigi Lilio), such as in the following:

A month after having decreed the reform, the pope (with a brief of 3 April 1582) granted to one Antoni Lilio, brother of Luigi Lilio, the exclusive right to publish the calendar for a period of ten years. The Lunario Novo secondo la nuova riforma[a] was printed by Vincenzo Accolti, one of the first calendars printed in Rome after the reform, notes at the bottom that it was signed with papal authorization and by Lilio (Con licentia delli Superiori... et permissu Ant(onii) Lilij). The papal brief was revoked on 20 September 1582, because Antonio Lilio proved unable to keep up with the demand for copies.[19]

The duplicate source should be removed (source 20). Alexanderjperry (talk) 15:26, 23 April 2019 (UTC)
 * Done, thank you for pointing this out. --John Maynard Friedman (talk) 19:03, 23 April 2019 (UTC)
 * Pictogram voting wait.svg Already done Nici<b style="color:purple">Vampire</b><b style="color:black">Heart</b> 21:52, 23 April 2019 (UTC)

External links update
We need to update the title "Today's date (Gregorian) in over 400 more-or-less obscure foreign languages" to "Today's date (Gregorian) in over 800 more-or-less obscure foreign languages" which is something I apparently don't have the editor status to do myself. Also, the link URL can be simply curiousnotions.com/todays-date now that I've overhauled the site in PHP. (At the moment I actually have 823 languages and dialects, though [groan] considering that I have a normal, offline life to live I don't intend to go much further.) Kukisvoomchor (talk) 09:09, 29 May 2019 (UTC) ✅ --John Maynard Friedman (talk) 09:41, 29 May 2019 (UTC)

Repetitions
I keep my calendars (a useful habit I picked up from mother) inasmuch as they repeat every seven years. Factoring in Leap Years, though, what the exact cycle? And factoring in movable feasts, what's the exact cycle? Thanks. kencf0618 (talk) 17:26, 10 October 2019 (UTC)
 * Factoring in leap years, the calendars repeat every 400 years. Factoring in moveable feasts, the calendar repeats in all respects every 5,700,000 years. See the Richards (2013) citation in the article, pages 598–599. Jc3s5h (talk) 17:36, 10 October 2019 (UTC)

Tibetan date in Tibetan?
In the fact box labeled »2020 in various calendars« under the item »Tibetan« the names of the Tibetan years are given in Chinese and English, but not in Tibetan. Could someone with the right knowledge and editor status do anything about that? Itsameno (talk) 17:03, 18 January 2020 (UTC)


 * That is a template used in many articles. Direct your suggestion to Template talk:Year in various calendars. — Joe Kress (talk) 02:06, 20 January 2020 (UTC)

Weekdays continuity
The article does mention that the continuity of the days of the week was maintained, but it would be useful to add what the days of the week were. Italian Wikipedia, for example, notes that Thursday Oct. 4 was followed by Friday Oct. 15.

24.136.4.218 (talk) 11:04, 19 April 2020 (UTC)

No mention of Pedro Chacón?
The Spanish mathematician Pedro Chacón was the one who redacted the Compemdium. Also, there is no hyperlink to the Alfonsine tables, that where the basis for using the calculations for the new calendar.

--178.237.229.242 (talk) 17:53, 28 May 2020 (UTC)

Semi-protected edit request on 3 June 2020
In the chart titled "Convertions from Julian to Gregorian dates", the "From" dates in the Julian column that start in February are 2 days too late for proper conversion as it would appear the author used a February with 30 days instead of 28.

Ex. In the second row the From Dates are: 1 March, 1700 (Gregorian) and 19 February, 1700 (Julian), however this only creates a difference of 9 days as February has 28 days not the 30 needed to have a difference of 11 days. Therefore the Gregorian From Date should be 3 March, 1700. 209.52.88.9 (talk) 12:26, 3 June 2020 (UTC)


 * The way the chart is to be used is to identify a Julian date to be converted, for example, 19 February 1700. See which row it falls into; it falls into the second row. Observe the difference is 11 days.
 * Recall that Thursday 4 October 1582 was followed by Friday 15 October 1582, so to find the Gregorian date one from the Julian date, one must count forward in the calendar 11 days:
 * 1 20 Feb.
 * 2 21 Feb.
 * 3 22 Feb.
 * 4 23 Feb.
 * 5 24 Feb.
 * 6 25 Feb.
 * 7 26 Feb.
 * 8 27 Feb.
 * 9 28 Feb.
 * 10 29 Feb. (1700 was a leap year in the Julian calendar)
 * 11 1 Mar.
 * I am not happy with this table because long convoluted instructions are required to understand whether one should be counting on the Gregorian calendar or the Julian calendar, and such instructions are absent. Jc3s5h (talk) 13:57, 3 June 2020 (UTC)

"Gregorian reform of the calendar" listed at Redirects for discussion
A discussion is taking place to address the redirect Gregorian reform of the calendar. The discussion will occur at Redirects for discussion/Log/2020 December 15 until a consensus is reached, and readers of this page are welcome to contribute to the discussion. Soumya-8974 (he) talk contribs subpages 17:40, 15 December 2020 (UTC)

"Gregorian calendar reform" listed at Redirects for discussion
A discussion is taking place to address the redirect Gregorian calendar reform. The discussion will occur at Redirects for discussion/Log/2020 December 15 until a consensus is reached, and readers of this page are welcome to contribute to the discussion. Soumya-8974 (he) talk contribs subpages 17:40, 15 December 2020 (UTC)

"15 October 1582" listed at Redirects for discussion
A discussion is taking place to address the redirect 15 October 1582. The discussion will occur at Redirects for discussion/Log/2020 December 15 until a consensus is reached, and readers of this page are welcome to contribute to the discussion. Soumya-8974 (he) talk contribs subpages 17:40, 15 December 2020 (UTC)

Proposal to change the citation style slightly, to use template:sfn
Being conscious of WP:CITEVAR and MOS:RETAIN, I thought it best to seek consensus for a small change I would like to make to the citation style used at present in this article. The article currently uses 'naked' references like Richards 1998, p. 101. If reader mouses over the reference number in a sentence like Before the 1969 revision of the Roman Calendar, the Roman Catholic Church delayed February feasts after the 23rd by one day in leap years; Masses celebrated according to the previous calendar still reflect this delay., all that pops up from the reference number [1] is Richards 1998, p. 101.

My proposal is to change this type of reference to. The cited sentence will still look the same to visitors: Before the 1969 revision of the Roman Calendar, the Roman Catholic Church delayed February feasts after the 23rd by one day in leap years; Masses celebrated according to the previous calendar still reflect this delay. and on mouse-over the reference number [2] they will still see Richards 1998, p. 101 but if they hold the mouse over, the pop-up will expand to the full book citation, which to me is a lot more convenient, IMO.

Of course it will mean that I will have to reformat the sources to use cite book, so will become
 * Richards, E. G. (2013). "Calendars". In S. E. Urban and P. K. Seidelmann (eds.), Explanatory Supplement to the Astronomical Almanac 3rd ed. (pp. 585–624). Mill Valley CA: University Science Books. ISBN 978-1-891389-85-6



Any objections? --John Maynard Friedman (talk) 11:47, 4 December 2020 (UTC)
 * It's OK with me. It looks like there is a book by Richards, and a book chapter by Richards. Also, some of these time & calendar related articles have references to different editions of the same book, so vigilance is needed. Jc3s5h (talk) 13:41, 4 December 2020 (UTC)

Book list
A big change so before I put it live, could someone check it please?




 * I have copied this revision to live. --John Maynard Friedman (talk) 12:34, 16 December 2020 (UTC)

Book list markup
. Your recent edits suggest you think the following would not work: Scientific American is a great magazine.

But it does work. The templates are able to extract the 1982 from the date and match it up with the 1982 from the sfn template. Jc3s5h (talk) 19:18, 15 December 2020 (UTC)
 * Thanks, that's good news. I couldn't find anything at sfn or cite to say it did so I didn't bother to try. Oh me of little faith. I will change it back. Did you have time to check any others? One item that worried me is that Worldcat is giving the same ISBN for all editions of the The Oxford companion to the year, but I suppose the change from ISBN-10 to ISBN-13 just exposed a pre-existing issue, it didn't create it. --John Maynard Friedman (talk) 19:36, 15 December 2020 (UTC)
 * ✅ --John Maynard Friedman (talk) 12:40, 16 December 2020 (UTC)
 * I checked the following book, which I own:
 * I checked that it sort of supports all the claims in the article, more on that later. The one I have was reprinted with corrections in 2003, so I would write the citation thus
 * World cat seems to say that ISBN goes with the 2003 corrected reprinting, and agrees with what is printed on page iv of mine.
 * In the article, the whole section "Difference between Gregorian and Julian calendar dates" is suspect because it describes one calculation, but supports it with more than one source (one of them is Blackburn & Holford-Strevens); who is to say the calculations in the two sources are compatible? The section extends the calculation before AD 1, but the book only gives dates in the 2nd and 3rd millennium as examples. Jc3s5h (talk) 20:37, 15 December 2020 (UTC)
 * ✅, though not identically. --John Maynard Friedman (talk) 12:40, 16 December 2020 (UTC)
 * I want to stick with tunnel vision for the moment, and just update the citation style. The question you raise is a valid one but best I leave it to you to resolve. (I have doubts about extending the proleptic Gregorian before 325 but I definitely think that we should not facilitate extension before the epoch, that way madness lies. --John Maynard Friedman (talk) 21:01, 15 December 2020 (UTC)
 * I have copied the list to live. Feel free to just revert if you see anything that needs further correcting because the version above is up to date and can more easily be revised and recopied to live when done. --John Maynard Friedman (talk) 12:40, 16 December 2020 (UTC)
 * I want to stick with tunnel vision for the moment, and just update the citation style. The question you raise is a valid one but best I leave it to you to resolve. (I have doubts about extending the proleptic Gregorian before 325 but I definitely think that we should not facilitate extension before the epoch, that way madness lies. --John Maynard Friedman (talk) 21:01, 15 December 2020 (UTC)
 * I have copied the list to live. Feel free to just revert if you see anything that needs further correcting because the version above is up to date and can more easily be revised and recopied to live when done. --John Maynard Friedman (talk) 12:40, 16 December 2020 (UTC)