Its establishment was part of the entry of the Grand Duchy of Lithuania into the rivalry for the religious control of the Rus ' principalities between Galicia -- Volhynia and the Grand Duchy of Moscow .
Volhynia is the Principality of Tver .
Its establishment was part of the entry of the Grand Duchy of Lithuania into the rivalry for the religious control of the Rus ' principalities between Galicia -- Volhynia , the Principality of Tver , and the Grand Duchy of Moscow .