In the Russian Orthodox church history, the Old Believers (Russian: старове́ры or старообря́дцы, read starovery or staroobryadtsy) became separated after 1666-1667. They split from the hierarchy of the Russian Orthodox Church as a protest against church reforms introduced by Patriarch Nikon. Old Believers continue liturgical practices which the Russian Orthodox Church followed before the reform.
Russian-speakers refer to the schism itself as raskol (раскол). This word comes from a Russian word расколоться, that means "to cleave apart").