Cyprian, an educated Hesychastic-oriented monk, was one of the most important representatives of the Orthodox church in medieval Eastern Europe. All of the measures which he carried out during his time as the Metropolitan of Kiev were aimed at maintaining the unity of the metropolis, covering the whole of Eastern Europe, regardless of political divisions. He used proposals for negotiating a church union to find a solution to the situation which had arisen after the foundation of the Polish-Lithuanian union, which presented the Orthodox church with a new situation. He continued the reforms to the monasteries in the Grand Duchy of Moscow, which helped create the conditions for the development of the Russian autocephalous church. After a critical period in the 1380s, he contributed towards the restoration of the authority of the Russian metropolis and the entire ecclesiastical hierarchy.