Struggle for the Unity of the Church
Cyprian's episcopate unfolded amid a contested division of jurisdiction over the Russian lands. Consecrated in 1375 as Metropolitan of Kiev, Rus', and Lithuania with the right of succession to the whole metropolitanate, he faced refusal from Moscow's Grand Prince Dmitri Donskoi, who after Alexius's death in 1378 appointed rivals without the consent of Constantinople.
The dispute was resolved only after years of struggle, when the council of Patriarch Antony IV in 1389 recognized Cyprian as the true bishop of all Rus'. Sources remember him as a zealot for the unity of the Russian lands, primarily responsible for uniting the Church across the Russian territories and the Grand Duchy of Lithuania.