© O. Lieberknecht, 1999
Extends from 1 Sept of the previous to 31 Aug of the given year. Used in Byzance, South Italy and Sicily, until 1087 used by the Papal curia
Starts with New Year's day, here either (
) 25 Dec of the previous or (
) 1 Jan of the given year. Used by the Papal curia from 1087 on and in late medieval Germany.
Extends from 24 Sept of the previous to 23 Sept of the given year. Introduced by Bede, later widely used, especially in Germany and by the Imperial chancellery
Extends from 1 Sept of the previous to 31 Aug of the given year, in accordance with the Byzantine usage of dating the creation of the world.
Extends from 25 Dec of the previous to 24 Dec of the given year. Style most widely used in the Middle Ages
Extends from 1 Jan to 31 Dec, today still in use.
Begins the year on 25 March of the previous (stilus pisanus) or on 25 March of the given year (stilus florentinus, mos anglicanus).
From 1 March of the given year to the last day of February of the subsequent year. Derived from the pre-Caesarian Roman style), used by the Merovingian Franks, ufficial style in Venice until 1797
Begins the year on the (movable) date of Easter Sunday of the given year. The year
(Easter Style) went from
to Holy Saturday
Easter Style was used especially in France until the 16th century (mos gallicus). This program calculates Easter only for the time after the Council of Nicea (325), assuming that Easter was the first Sunday after the first official full moon on or after the official vernal equinox (21 March). Easter dates from 1583 on are given according to the Gregorian calendar reform of 15 Oct 1582, and are calculated with the official full moon. Many countries, however, adopted the Gregorian calendar only much later, and some protestant countries temporarily based their Easter computus not on the 'official' but on the actual full moon.