Boyarynya Morozova painting by Vasily Surikov depicting a defiant Old Believer arrested by Tsarist authorities in 1671. She holds two fingers raised: a hint of the old (i.e. "proper") way of cross-signing oneself: with two fingers, rather than with three.

In the context of Russian Orthodox church history, the Old Believers (Russian: старове́ры or старообря́дцы) separated after 1666-1667 from the hierarchy of the Church of Russia as a protest against church reforms introduced by Patriarch Nikon of Moscow.
Old Believers continue liturgical practices which the Russian Orthodox Church maintained before the implementation of these reforms. Because of the use of these older liturgical practices, they are also known as 'Old Ritualists, especially by those who recognize the faith of the Old Believers as being identical with mainstream Orthodoxy.
Russian-speakers refer to the schism itself as raskol (раскол - etymologically indicating a "cleaving-apart").