Gregory the Bulgarian

Born in Bulgaria, Gregory was an Eastern Orthodox Christian. He became an aide to Isidore, Metropolitan of Kiev and All Rus', who signed the act of union with the Roman Church on behalf of the Russian Church at the Council of Florence in 1439.

In 1458, he was appointed as the metropolitan of the newly-established Kiev see by the titular Latin Patriarch Gregory Mammas of Constantinople on agreement of the Pope Pius II.[2] Election Gregory was also supported by most of diocesan bishops of the original Old Russian Church among which were bishops of Przemysl, Chelm, Halych, Turow, Volodymyr, Lutsk, Polotsk, and Smolensk, while against were at least two metropolitan bishop in Moscow and Chernihiv.[3][4] At least two more diocesan bishops of Great Novgorod and Tver chose to abstain in selection either side.[4][lower-alpha 1] In 1469 the Ecumenical Patriarch of Constantinople Dionysius I also gave his blessings approving the appointment of Gregory,[4] thus Gregory in 1470 returned from the union.

The Patriarch gave the new Metropolitan the title of the Metropolitan of Kiev, Halych and All Rus'. (Prior to that, in 1448, Russian bishops in Moscow, who had rejected the Union with Rome, elected Jonas as Metropolitan of Kiev and All Rus'[5] without the consent from Constantinople.) The Polish-Lithuanian rulers accepted him, but he was rejected by the Grand Duchy of Moscow, whose metropolitans after 1461 abandoned the "Kiev" title and took on the new title of "metropolitan of Moscow and all Rus'".

The Kiev metropolinate within the Polish kingdom and the Grand Duchy of Lithuania under the rule of metropolitan Gregory (1458–1472) remained therefore in communion with the Holy See, as well as during the rule of the following metropolitan Міsail (1476–1480).

Later during signing of the Union of Brest, the appointment of Gregory was mentioned by Michael Rohoza.[2]

• Ukrainian Catholic Church: part 1.
• The Ukrainian Greek Catholics: A Historical Survey