The Schism of the Russian Church, also known as Raskol (Russian: Раскол, pronounced [rɐˈskoɫ], meaning 'split' or 'schism'), was the splitting of the Russian Orthodox Church into an official church and the Old Believers movement in the 1600s. It was triggered by the reforms of Patriarch Nikon in 1653, which aimed to establish uniformity between Greek and Russian church practices. In the 1630s and 1640s, Nikon had been a part of a group known as the Zealots of Piety, a circle of church reformers whose acts included amending service books in accordance with the "correct" Russian tradition. When Nikon became Patriarch of Moscow in 1652, he continued the practice of amending books under the guidance of Greek Orthodox advisors, changing practices in the Russian Church to align with the Greek rite. This act, along with the acceptance of the Nikonian reforms by Tsar Alexei Mikhailovich and the state, led to the rupture between Old Believers and the newly reformed church and state.
The schism contributed to popular uprisings in the late 1600s, including the Solovetsky Monastery uprising and the Moscow uprising of 1682, but by the time of Peter the Great in the early 1700s, much of the popular uproar had waned. Despite persecution, Old Believer communities have persisted to the present day, chiefly in Russia and Eastern Europe.