The Russian Orthodox Church (ROC) dates back to the "Kievan Rus" period (the first organized Russian state). In 988, Prince Vladimir, in order to gain an alliance with the powerful Byzantine Empire, declared Christianity as the religion of his realm, and mandated the baptism of Kiev's population and the construction of cathedrals. During the Mongol occupation (1240–1480), the head of the ROC (Metropolitan) was moved to Moscow. Throughout the reign of the tsars, Orthodoxy was synonymous with autocracy and national identity. After the Communist revolution of 1917, the Soviet government, based on Marxism, imposed a dogma of militant atheism and subordinated the ROC through fear and persecution. Other Christians, Muslims, and Jews were also oppressed (anti-Semitism was widespread before and after the 1917 revolution). Since 1985 and the subsequent dissolution of the Soviet Union, thousands of churches have been reopened; freedom of religion was incorporated into the draft constitution of 1993.
According to a 2001 report from the Ministry of Justice, there are about 20,215 registered religious groups in the country. The Russian Orthodox Church had the largest number, with about 10,912 groups. Islam is the largest minority religion, with about 3,048 registered groups and, perhaps, over a thousand unregistered groups. Protestants make up the third largest group of the country with a a variety of denominations, including Baptists, Lutherans, Methodists, Presbyterians, the Church of Christ, and others. There are about 197 Jewish registered groups, with an estimated 600,000 to 1,000,000 Jews in the country. There are 106 registered groups of Hare Krishnas. Hindus, Scientologists, Christian Scientists, Taoists, Baha'is, Zoroastrians,
Buddhists, Karaites, and Shamanists are also represented with one to 20 groups each. There are about 41 registered pagan groups.