Inter gravissimas (English: "Among the most serious...") was a papal bull issued by Pope Gregory XIII on 24 February 1582.[1][2] The document, written in Latin, reformed the Julian calendar. The reform came to be regarded as a new calendar in its own right and came to be called the Gregorian calendar, which is used in most countries today.
- ^ Inter Gravissimas Bill Spencer's (in English) translation of the Inter Gravissimas, 1999, revised 2002, based on Rodolphe Audette's transcription of the (in Latin) text. Also includes Rodolphe Audette's translation into (in French).
- ^ Inter Gravissimas prepared for ISO TC 154 (in English, Latin, and French)