section_path: Constituencies
section_name: Constituencies
paragraph_text: Constituencies
  
  The various autocephalous and autonomous synods of the Eastern Orthodox Church are distinct in terms of administration and local culture, but for the most part exist in full communion with one another. However, there have been varying instances in the history of the Eastern Orthodox Church where communion has been broken between member churches for short periods, particularly over autocephaly issues or disagreements over ecumenism with other Christian denominations. In addition, some schismatic churches not in any communion exist, with all three groups identifying as Eastern Orthodox.
  
  Another group of non-mainstream Eastern Orthodox Christians are referred True Orthodoxy or Old Calendarists; they are those who, without authority from their parent churches, have continued to use the old Julian calendar, and split from their parent church.
  
  The Russian Orthodox Church Outside Russia (ROCOR) has united in 2007 with the Moscow Patriarchate; these two churches had separated from each other in the 1920s due to the subjection of the latter to the hostile Soviet regime.
  
  Another group called the Old Believers, separated in 1666 from the official Russian Orthodox Church as a protest against church rite reforms introduced by Patriarch Nikon of Moscow.