Old Calendarists
Old Calendarists are groups of Orthodox Christians who are in various levels of "resistance" against the mainstream Orthodox churches, identified mainly by their insistence on the use of the Julian calendar. They are to be distinguished from the mainstream churches which simply follow the Old Calendar yet remain in communion with most of world Orthodoxy. Many Old Calendarists today say that their concerns about ecumenism are more significant than calendar issues.
Some Old Calendarist groups are styled as True Orthodox or Genuine Orthodox.
Churches "in resistance"
These churches refrain from concelebration with the mainstream Orthodox churches, but do not consider themselves schismatic, nor have they declared a break in communion with the mainstream churches. They will also commune the faithful of those churches.
- Holy Synod in Resistance ("Cyprianites")
- Old Calendar Orthodox Church of Romania
- Old Calendar Orthodox Church of Bulgaria
Churches which are "walled off"
These churches refrain from both concelebration and communion with the mainstream Orthodox churches, regarding those mainstream churches to have apostasized and placed themselves outside Orthodoxy.
