Great Moscow Synod
The Great Moscow Synod was a Pan-Orthodox synod convened by Tsar Alexis of Russia in Moscow in April 1666 in order to depose Patriarch Nikon of Moscow.
It was led by Patriarch Païsius of Alexandria, and attended by Patriarchs Macarios of Antioch and Nikon of Moscow, the Metropolitan of Iconium Athanasius, and Ananias of Sinai, among many other bishops and fathers.
The council condemned the famous Stoglav of 1551 as heretical, because it had dogmatized the native Russian church rituals and usage at the expense of those accepted in Greece and other Orthodox countries. This decision precipitated a great schism of the Russian Orthodox Church known as the Raskol. Avvakum and other leading Old Believers were brought to the synod from their prisons. Since they refused to revise their views, the Old Believer priests were defrocked, anathemized and sentenced to life imprisonment in distant monasteries.
On 12 December 1666 the council pronounced Nikon guilty of reviling the tsar and the whole Muscovite Church, of deposing Paul, bishop of Kolomna, contrary to the canons, and of beating and torturing his dependents. His sentence was deprivation of all his sacerdotal functions; henceforth he was to be known simply as the monk Nikon.
One of the decisions in the synod was a specific ban on a number of depictions of God the Father and the Holy Spirit, which then also resulted in a whole range of other icons being placed on the forbidden list. See God the Father in Western art for details.