Religion was suppressed to one degree or another during most of the Soviet era, but has since become freely practiced again. Russian Orthodoxy, a Christian denomination, constitutes the country's largest religious group by number of adherents, roughly one-sixth of Russia's population. Other Christian groups are significantly smaller. Among them are the Old Believers, who diverged from Orthodoxy in the 17th century over liturgical differences. Most of Russia's Turkic minority groups are Muslim. Among the many non-Russian groups that inhabit Siberia and other more remote areas, some still adhere to older, shamanistic belief systems.
("Russia," Encyclopedia Britannica)