1652–1667

Patriarch Nikon's Reform and the Old Believer Schism

Nikon became Patriarch in 1652. Tsar Alexei Mikhailovich dreamed of Constantinople. Acting on the Tsar's political ambitions, Nikon ordered the Russian liturgical books and rites corrected to match contemporary Greek models.

His opponents held that the "Third Rome" should not conform to a fallen Constantinople. They drew support from monks and the lower classes. They formed the Old Believer party, led by the exiled Archpriest Avvakum.

The Great Moscow Council of 1666–1667 condemned the Old Believers. Force was used against them: a besieged monastery was stormed and its monks killed. Thousands resorted to mass self-immolation. The movement split into "priestly" and "priestless" factions.