Timeline of official adoptions of Christianity

This is a timeline showing the dates when countries or polities made Christianity the official state religion, generally accompanying the baptism of the governing monarch.

Adoptions of Christianity to AD 1450

 * c. 34 or 200 – Osroene – disputed; both dates claimed
 * 179 – Silures; traditional date, now considered questionable
 * 301 – Christianization of Armenia
 * 301 - Foundation of San Marino
 * c. 313 – Caucasian Albania (Udi)
 * c. 319 – Christianization of Iberia (Georgia)
 * c. 325 – Kingdom of Aksum (Ethiopian Orthodox Church)
 * 337 – Roman Empire (baptism of Constantine I)
 * 361 – Rome returns to paganism under Julian the Apostate
 * 364 – Rome returns to Christianity, specifically the Arian Church
 * c. 364 – Vandals (Arian Church)
 * 376 – Goths and Gepids (Arian Church)
 * 380 – Rome goes from Arian to Catholic/Orthodox (both terms are used refer to the same Church until 1054)
 * 411 – Kingdom of Burgundy (Nicene Church)
 * c. 420 – Najran (Nicene Church)
 * 448 – Suebi (Nicene Church)
 * c. 450 – Burgundy goes from Nicene to Arian
 * 451 – Aksum and Najran are Coptic with Chalcedonian Schism.
 * 466 – Suebi go from Chalcedonian to Arian
 * 473 – Ghassanids (Chalcedonian Church)
 * 480 – Lazica (Chalcedonian Church)
 * 496 – Franks (Chalcedonian Church)
 * 506 – Iberia goes from Chalcedonian to Apostolic
 * c. 510 – Ghassanids go from Chalcedonian to Coptic
 * 516 – Burgundy returns from Arian to Chalcedonian
 * c. 543 – Makuria (Chalcedonian), Nobatia and Alodia (Coptic Church)
 * c. 550 – Suebi return from Arian to Chalcedonian
 * c. 558 – Christianization of Ireland (Celtic Church)
 * c. 563 – Picts (Celtic Church)
 * c. 568 – Lombards (Arian Church)
 * 569 – Garamantes (Chalcedonian Church)
 * 589 – Visigoths go from Arian to Chalcedonian
 * 591 – Lombards go from Arian to Chalcedonian
 * c. 592 – Lakhmids (Nestorian Church)
 * 601 – Kent (Chalcedonian Church)
 * 604 – East Anglia and Essex (Chalcedonian)
 * 607 – Iberia returns from Apostolic to Chalcedonian
 * 610 – Armenia and Caucasian Albania go from Chalcedonian to Apostolic
 * 616 – Kent and Essex return to paganism
 * c. 620 – Alemanni (Chalcedonian Church)
 * 624 – Kent returns from pagan to Chalcedonian
 * 627 – Lombards return from Chalcedonian to Arian
 * 627 – Northumbria – (Chalcedonian Church); East Anglia returns from Chalcedonian to pagan
 * 630 - East Anglia returns from pagan to Chalcedonian
 * 635 – Wessex (Chalcedonian Church)
 * 653 – Lombards return from Arian to Chalcedonian
 * 653 – Essex returns from pagan to Chalcedonian
 * 655 – Mercia (Chalcedonian Church)
 * 675 – Sussex (Chalcedonian Church)
 * 692 – Ireland goes from Celtic to Chalcedonian
 * 696 – Bavaria (Chalcedonian)
 * c. 700 – Circassia (most of the country would remain pagan)
 * 710 – Picts go from Celtic to Chalcedonian
 * c. 710 – Makuria goes from Chalcedonian to Coptic
 * 724 – Thuringia
 * 734 – Frisians
 * 785 – Saxons
 * c. 805 Duchy of Lower Pannonia
 * 840s – Navarre
 * 863 – Moravia
 * 864 – Christianization of Bulgaria
 * c. 869 – Christianization of the Serbs
 * 879 – Duchy of Croatia
 * 884 – Bohemia
 * 911 – Normans
 * 960 – Denmark
 * 966 – Christianization of Poland
 * c. 989 – Christianization of Kievan Rus'
 * 995 – Norway
 * 999 – Faroe Islands
 * c. 1000 Christianization of Hungary with the first real Christian king(Roman Catholic became official but Orthodox(Eastern) existed as well since 973 onwards even after 1054).
 * c. 1000 – Christianisation of Iceland
 * 1007 – Kerait Khanate – Nestorian Church
 * c. 1008 – Sweden
 * 1054 – Byzantine Empire, Kingdom of Georgia, Bulgaria, Serbs, and Rus' are Orthodox Catholics with East-West Schism while Western Europe becomes Roman Catholic
 * 1124 – Conversion of Pomerania
 * 1160s – Obotrites
 * c. 1200 – (Southwestern) Finland
 * 1227 – Livonia (including mainland Estonia and northern Latvia), Cumania (Transylvania)
 * 1241 – Saaremaa
 * 1260 – Curonians
 * 1290 – Semigallians
 * 1387 – Christianization of Lithuania
 * 1413 – Samogitia

Adoptions after 1450

 * 1491 – Kingdom of Kongo (Roman Catholic Church)
 * 1519 – Tlaxcala (Roman Catholic Church)
 * 1521 – Rajahnate of Cebu (Roman Catholic Church)
 * 1523 – Sweden goes from Catholic to Lutheran
 * 1528 – Schleswig-Holstein goes from Catholic to Lutheran
 * 1534 – England goes from Catholic to Anglican
 * 1536 – Denmark-Norway and Iceland go from Catholic to Lutheran
 * 1553 – England returns from Anglican to Catholic
 * 1558 – Kabardia (E. Orthodox Church)
 * 1558 – England returns from Catholic to Anglican
 * 1560 – Scotland goes from Catholic to Presbyterian
 * 1610 – Mi'kmaq (Roman Catholic Church)
 * 1624 – Kingdom of Ndongo (Roman Catholic Church)
 * 1624 – Ethiopia goes from Coptic to Catholic
 * 1631 – Kingdom of Matamba (Roman Catholic Church)
 * 1633 – Ethiopia returns from Catholic to Coptic
 * 1640 – Piscataway (Roman Catholic Church)
 * 1642 – Huron-Wendat Nation (Roman Catholic Church)
 * 1650 – Kingdom of Larantuka (Roman Catholic Church)
 * 1654 – Onondaga (Roman Catholic Church)
 * 1663–1665 – Kingdom of Loango (briefly Roman Catholic)
 * 1675 – Illinois Confederation (Roman Catholic Church)
 * 1700s – Kingdom of Bolaang Mongondow (Reformed Church)
 * 1819 – Kingdom of Tahiti, Kingdom of Hawaii (Congregational Church)
 * 1829 – Spokane, Kutenai (Anglican Church)
 * 1830 – Samoa (Congregational Church)
 * 1838 – Nez Perce (Presbyterian Church)
 * 1869 – Merina Kingdom (Reformed Church)
 * 1882 – Blackfoot Confederacy (Roman Catholic Church)
 * 1880 – Shoshone (LDS Church)
 * 1884 – Lakota (Roman Catholic Church)
 * 1884 – Catawba (LDS Church)
 * 1897 – Shoshone go from LDS to Anglican
 * 1907 – Arapaho (Baptist Church)