The Orthodox churches began preparing for a great council in the 1960s. Agendas were drafted, narrowed and redrafted; contentious items were removed to protect consensus; preparatory conferences met over decades. The rule adopted was that everything would be decided unanimously, each autocephalous church speaking with one voice, and that no document would go forward that any church rejected.
The council opened in Crete in June 2016 with four of the fourteen generally recognised autocephalous churches absent. Antioch stayed away over a jurisdictional dispute with Jerusalem about Qatar. Bulgaria withdrew over the texts and over practical arrangements. Georgia withdrew over the documents on marriage and on relations with other Christians. The Russian Orthodox Church, by a wide margin the largest, declined to attend once the others had, arguing that a council without them would not be pan-Orthodox.
The remaining ten met and adopted six documents and an encyclical, on the mission of the church, the Orthodox diaspora, autonomy, marriage, fasting and relations with the rest of the Christian world. Delegations were capped at twenty-four bishops each, so the council was small by the standards of the ancient ones and very small beside Vatican II.
Whether to proceed without the absent four was itself a decision, taken on the principle that a church which stays away cannot prevent a council from meeting. That principle is not new and it is not universally accepted, and the argument about it began immediately.