The Gregorian calendar, which was adopted by papal bull in 1582, replaced which other western calendar?
Gregorian calendar 12 seconds. The Gregorian calendar was a reform of the Julian calendar. It was instituted in 1582 by Pope Gregory XIII, after whom the calendar was named, by papal bull "Inter gravissimas" dated 24 February 1582. The motivation for the adjustment was to bring the date for the celebration of Easter to the time of year in which it was celebrated when it was introduced by the early Church. The error in the Julian calendar (its assumption that there are exactly 365.25 days in a year) had led to the date of the equinox according to the calendar drifting from
Gregorian calendar 4 October 1582 was followed by the first day of the Gregorian calendar, Friday, 15 October 1582 (the cycle of weekdays was not affected). Although Gregory's reform was enacted in the most solemn of forms available to the Church, the bull had no authority beyond the Catholic Church and the Papal States. The changes that he was proposing were changes to the civil calendar, over which he had no authority. They required adoption by the civil authorities in each country to have legal effect. The bull "Inter gravissimas" became the law of the Catholic Church in 1582, but it was