Russian Orthodoxy is the body of several churches within the larger communion of Eastern Orthodox Christianity, whose liturgy is or was traditionally conducted in Church Slavonic language. Most Churches of the Russian Orthodox tradition are part of the Eastern Orthodox Church.
Trinity by Andrei Rublev
15th–16th century Moscow–Constantinople schism
The schism between the Ecumenical Patriarchate and part of its Metropolis of Kiev and all Rus occurred between approximately 1467 and 1560. This schism de facto ended supposedly around 1560.
Isidore of Kiev