The Russian Orthodox Church (ROC; ), alternatively legally known as the Moscow Patriarchate , is one of the autocephalous Eastern Orthodox churches, in full communion with other Eastern Orthodox patriarchates. The Primate of the ROC is the Patriarch of Moscow and all Rus'. The ROC, as well as the primate thereof, officially ranks fifth in the Orthodox order of precedence, right under the four ancient Patriarchates of the Greek Orthodox Church, those of Constantinople, Alexandria, Antioch, and Jerusalem. The official Christianization of Kievan Rus' widely seen as the birth of the ROC is believed to have occurred in 988 through the baptism of the Kievan prince Vladimir and his people by the clergy of the Ecumenical Patriarchate whose constituent part the ROC remained for the next six centuries, while the Kievan see remained in the jurisdiction of the Ecumenical Patriarchate until 1686.