Moscow's religious standing was built deliberately. The metropolitan of Kyiv and all Rus moved his residence to the town in the early fourteenth century, which gave a minor principality the senior churchman of the Rus lands, and the monastery Sergius of Radonezh founded to the north supplied both a school of monastic renewal and a saint attached to Moscow's military fortunes. When Constantinople accepted union with Rome at Florence and then fell to the Ottomans, Moscow rejected the union, appointed its own metropolitan without Constantinople's consent, and began to think of itself as the surviving centre of Orthodoxy. The monk Filofei of Pskov put the claim in a form that has been quoted ever since: two Romes have fallen, a third stands, and a fourth there will not be. A patriarchate followed in 1589.
The most damaging quarrel in Russian church history was about ritual. Patriarch Nikon revised the service books and the manner of crossing oneself to match contemporary Greek usage, and in 1666 and 1667 councils anathematised those who refused. The Old Believers who refused included whole communities, and their leader Avvakum was burned in 1682; the movement survives to this day and its priestless branches developed forms of worship without clergy at all.
Peter the Great abolished the patriarchate in 1721 and replaced it with a Holy Synod of appointed members under a lay official, which left the church without a head for nearly two hundred years and moved its administration to the new capital on the Baltic.