Revised Julian calendar
The Revised Julian calendar was first used as a civil calendar in Greece and was later adopted by some Eastern Orthodox churches. A minority of Eastern Orthodox Christians regarded this as a surrender of the Eastern Orthodox Church to the Pope and continued following the old, Julian calendar. Some of these also broke communion with those who had adopted the new calendar, thus creating their own church, or denomination. This schism is the beginning of the Old Calendar Churches which suspended full communion or concelebration with other Eastern Orthodox churches ("New Calendarists") over the adoption by the latter of the Revised Julian calendar (called "New Calendar," although some churches did not specify the details of which "New calendar" they were adopting).