Cardinal, classical scholar, born Trebizond, Asia Minor; died Ravenna, Italy.
In 1436 he was made Bishop of Nicaea, and accompanied John VII Palreologus to Ferrara, where he contributed much to bring about the real union of the Churches, 1439; later he was made cardinal and embraced the Latin Rite.
In 1443 he became Bishop of Sabina and in 1449 of Frascati.
From 1450 to 1455, as governor of Bologna, he calmed internal factionism, restored the university, and promoted classical studies.
After the fall of Constantinople, he labored unceasingly to save the Oriental Christians, and was rewarded for his efforts with the commendatory abbacy of the Greek Basilians at Grottaferrata; subsequently he was named Patriarch of Constantinople.
In 1463 he succeeded in allying Venice and Matthias Corvinus against the Turks.
He established the first Roman academy to revive interest in the ancient classics and was very successful, but his hopes of permanent Church reunion and of Turkish expulsion were unfulfilled.
He bequeathed his Greek codices to Venice, where they formed the nucleus of the Library of Saint Mark.
New Catholic Dictionary