9) The Old Calendarist Schism of the 1920's.
The Old / New Calendar Schism of the 1920's
There has been a simply massive schism in Orthodoxy over the decision of many in their church to drop the old Julian Calendar, and adopt the Gregorian Calendar (see Calendars). I cannot presently obtain statistics on just what percentage ratio of (what amounts to) the two denominations believe in using which calendar (though the new calendar is seldom strictly Gregorian, as the date of Easter shows) Let me emphasise - the division over calendars has been colossal! And in effect the practical characterization of the two halves of their church are that the old calendarists are legalistic and dogmatic, and the new calendarists are less legalistic less likely to stick to all the old traditions, like "You cannot sit down in church" or "you cannot play music in church" or "you cannot sing a hymn in church" etc etc.. However a large number of the old calendar believers do not see one church divided over calendar issues, they say the other side have graceless sacraments and no authority even to marry two people.
See Revised Julian Calendar:
"The Revised Julian Calendar" with a new leap year rule proposed by the astronomical delegate Milutin Milankovic. This became a huge schism in Orthodoxy, wherein 3 schisms away from the main percentage ratio formed what are in effect at least 3 religions (each claiming to be the original religion). So how many of these "religions" have a Titular Head of Orthodoxy, and does each have an independent genealogy of their Titular Head? (I have no researched this yet).
Old Calendarists: There are at least three types,
3) The Matthewites.
all of which have factions within themselves.