Wikipedia:Leadcruft

The lead sentence of an article is critically important. Not only does it establish the context and importance of the subject, but in many cases (such as search results or Hovercards) it is the only part of an article that actually gets read. Over the years, Wikipedia lead sentences have become dumping grounds for any and all metadata about an article subject, to the point of becoming virtually unreadable. While some of this information is useful for establishing context, at lot of it is just cruft that actually degrades the quality of the lead. It is important to be thoughtful about what we do and do not include in lead sentences so that we strike a balance between too much information and too little. Most importantly, a lead sentence should never get to the point of including so much metadata that it becomes difficult to read.

Examples of lead sentence cruft
These are examples of actual lead sentences that were cluttered with too much cruft:


 * Wu Zetian (Wu Tse-t'ian; ) (February17, 624 – December16, 705),[1] also known as Wu Zhao (Wu Chao; ) or Wu Hou during the Tang dynasty as Tian Hou (天后), and in English as Empress Consort Wu, or by the deprecated term,[2] "Empress Wu", was a Chinese sovereign, who ruled officially under the name of her self-proclaimed "Zhou dynasty", from 690 to 705.


 * Hyperopia or hypermetropia, from the Greek word "hyper-metropia : ὑπερ-μετρωπία" (hyper = over + metro = measure + op = sight, look + suffix ia = condition, state > thus a condition of over-measured sight) commonly known as being farsighted (American English) or longsighted (British English), is a defect of vision caused by an imperfection in the eye (often when the eyeball is too short or the lens cannot become round enough), causing difficulty focusing on near objects, and in extreme cases causing a sufferer to be unable to focus on objects at any distance.


 * Atrophodermia vermiculata (also known as "Acne vermoulante," "Acne vermoulanti," "Atrophoderma reticulata symmetrica faciei," "Atrophoderma reticulatum," "Atrophoderma vermiculata," "Atrophoderma vermiculatum," "Atrophodermia reticulata symmetrica faciei," "Atrophodermia ulerythematosa," "Atrophodermie vermiculée des joues avec kératoses folliculaires," "Folliculitis ulerythema reticulata," "Folliculitis ulerythematous reticulata," "Folliculitis ulerythemosa," "Honeycomb atrophy," "Ulerythema acneforme," and "Ulerythema acneiforme") presents with erythematous follicular papules on the cheeks in childhood, and, with time, the lesions develop into pit-like depressions.


 * Christopher Columbus (Cristoffa Combo; Cristoforo Colombo; Cristóbal Colón; Cristóvão Colombo; Christophorus Columbus; born between 31 October 1450 and 30 October 1451 in Genoa – died on 20 May 1506 in Valladolid) was an Italian explorer, navigator, colonizer, and citizen of the Republic of Genoa.

Things to not include in lead sentences
According to Wikipedia's style guide, you should avoid including the following things in lead sentences:
 * Pronunciations for common English words or names
 * Pronunciations that are apparent from a word's spelling
 * Birth and death place (unless they are directly relevant to the person's notability)
 * More than two alternative names
 * More than one foreign language name
 * Etymology