The Coptic calendar, also called the Alexandrian calendar, is a liturgical calendar used by the Coptic Orthodox Church and also used by the farming populace in Egypt. It was used for fiscal purposes in Egypt until the adoption of the Gregorian calendar on 11 September (6 Nesi) 1875. This calendar is based on the ancient Egyptian calendar. To avoid the calendar creep of the latter (which contained only 365 days each year, year after year, so that the seasons shifted about one day every four years), a reform of the ancient Egyptian calendar was introduced at the time of Ptolemy III (Decree of Canopus, in 238 BC) which consisted of adding an extra day every fourth year. However, this reform was opposed by the Egyptian priests, and the reform was not adopted until 25 BC, when the Roman Emperor