In Kilifarevo monastery Cyprian met with future Bulgarian patriarch (between 1375 and 1393) Euthymius, who also was studying hesychasm and was later regarded as one of the most important figures of medieval Bulgaria.

[8] In 1371, the united metropolis was officially lowered to the rank of a bishopric and placed under the jurisdiction of the Metropolitan of Kiev and all Rus'.

[2] In winter of the same year, it is possible that Cyprian visited Kiev for the first time along with other cities of the Grand Duchy of Lithuania.

He attempted, but failed, to get recognition of his rights in the metropolitan diocese from the Grand Duke of Moscow — Dmitri Donskoi.

In fear of his life both from the Grand Duke as well as the approaching armies of Tokhtamysh, Cyprian chose to live either in Lithuania or at Constantinople.

[6] On 12 February 1378, Alexius died; by the terms of the agreement with the patriarch, Cyprian was entitled to rule the religious affairs of all Rus'.

In February 1389, Patriarch Antony IV of Constantinople convened a council that restored the unity of the metropolis by finally recognizing Cyprian as "the true bishop of all Rus'".

In 1390, Cyprian returned to Moscow and was recognised as the legitimate Metropolitan of Kiev and all Rus' by the new Grand Prince — Vasili II.

During his term, his main objectives were to preserve a unified metropolis in Rus' and to secure peace with Lithuania.

He faced serious opposition during his metropolitanate; Dmitry Donskoy and his advisors were excommunicated for opposing Cyprian's efforts to take up his place in Moscow, and Novgorod the Great – especially Archbishops Aleksei and Ioann II – also opposed his efforts to adjudicate ecclesiastical cases there, which would have allowed him to gain the court fees from Novgorod during the time he sat in judgement there.

He oversaw the copying and creation of a number of important works, including the Troitskaia Chronicle (or Troitskaya letopis) and, probably, the Metropolitan Justice (also known as the Pravosudiye metropolich’ye or Правосудие митрополичье).

[10] The Book of Degrees (Stepénnaya kniga), which grouped Russian monarchs in the order of their generations, was started by Cyprian in 1390 (but completed only in 1563).