ISIDORE OF KIEV

Humanist, Greek cardinal, and promoter of union of Florence; b. Monembasia, Greece, c. 1385; d. Rome, May 27, 1464. After being educated in Constantinople, Isidore became a monk in Monembasia and later abbot of the convent of Demetrius, Constantinople. Sent as envoy of the Emperor John VIII to the Council of Basel in 1434 to arrange for a council of union, he returned to Constantinople in the summer of 1435, and in 1436 was consecrated metropolitan of Kiev and all Russia. He arrived in Moscow on April 2, 1437, and almost immediately started on his way to the Council of Ferrara-Florence. He reached Ferrara only in mid-August 1438 and was elected one of the six Greek spokesmen in the Council. He had little occasion to speak, though he was throughout a force for union. In the months after the dogmatic sessions of March 1439 he was particularly active with bessarion and others, and he had the confidence of both Emperor and Pope. He signed the decree of union, acting also as procurator for Antioch, and was nominated Apostolic Legate on August 17 for the Russias, and created cardinal on December 18. He issued an encyclical from Buda stressing the equality of the Churches; he was at first well received in Kiev and promulgated the union in Moscow (March 1441), but he was imprisoned on a charge of heresy by the Great Prince. Having escaped and been reimprisoned in Tver, he spent a year in Galizia, working for union; he then returned to Italy. After serving as legate on a mission to Greece (1444–48), he went to Constantinople in 1452 as papal legate and promulgated (Dec. 12) the union of Florence. He was wounded in the fall of the city and taken prisoner, but he escaped. Invested with the temporalities of the Latin patriarchate of Constantinople in 1452, he was appointed Greek patriarch on April 20, 1459, after resigning all his offices except the bishopric of Moscow (1458).

He was a notable humanist, interested in philosophy, mathematics, astronomy, and other branches of learning. Of his writings there remain a discourse in reply to Cardinal Cesarini at Basel, the unfinished drafts of several speeches prepared at Florence, a valuable report on the Eastern Church of c. 1448, and a treatise on the Procession of the Holy Spirit, as well as letters in Greek and Latin; the first of these items and many of the letters have been published.

Bibliography: g. mercati, Scritti d'Isidoro il cardinale ruteno (Studi e Testi 46; 1926). g. hofmann, "Quellen zu Isidor von Kiew," Orientalia Christiana periodica 18 (1952) 143–157. a. ziegler, Die Union des Konzils von Florenz in der russischen Kirche (Würzburg 1938). j. gill, "Isidore, Metropolitan of Kiev," Personalities of the Council of Florence (New York 1964) 65–78.

[j. gill]