Eastern Orthodox Christianity was the country’s dominant religion for a thousand years since the 10th century, when Vladimir I, grand prince of Kiev and ruler of the Kievan Rus’, was converted to Christianity by Byzantine missionaries. The Russian Orthodox church suffered under communist rule, but the dissolution of the Soviet Union gave way to religious freedom. Majority of Russians belong to the Russian Orthodox church, which consider the Ecumenical Patriarch of Constantinople as primus inter pares (first among equals) among the heads of Orthodox churches worldwide.