no oriental orthodox churches are currently in communion with the eastern orthodox. they use the old calendar or their own calendars. most of the armenian church has adopted the gregorian calendar, though the armenian patriarchate of jerusalem uses the old calendar; no armenian churches now use the armenian calendar. the indian orthodox church uses the gregorian calendar along with their autonomous syriac orthodox counterparts in india, the malankara jacobite syriac orthodox church, in contrast to the rest of the syriac church which uses its own calendar. the ancient church of the east (julian calendar) emerged as the result of a schism when patriarch shimun xxi eshai introduced the gregorian calendar into the assyrian church of the east.