The Ethiopian calendar, or Geʽez calendar is the official state civil calendar of Ethiopia and serves as an unofficial customary cultural calendar in Eritrea, and among Ethiopians and Eritreans in the diaspora. It is also an ecclesiastical calendar for Ethiopian Christians and Eritrean Christians belonging to the Orthodox Tewahedo Churches, Eastern Catholic Churches, and Protestant Christian P'ent'ay Churches. The Ethiopian calendar is a solar calendar that has much in common with the Coptic calendar of the Coptic Orthodox Church of Alexandria and Coptic Catholic Church, but like the Julian calendar, it adds a leap day every four years without exception, and begins the year on 11 or 12th of September in the Gregorian calendar. Its epoch equates to 29 August 8 AD. The neighbouring Coptic calendar is very similar to the Ethiopian calendar, except that it has a different epoch and different names for the days of the week and months of the year.