Bessarione was a cardinal and Byzantine humanist. Born in a large and poor family in Trebizond, then capital of the small empire commanded by the Mega Comneni. His presumed comnena origin - affirmed by later sources and silenced by all his contemporaries who instead want him with modest origins - is difficult to ascertain. For centuries his first name was considered John, but more recent studies have shown that it was Basil. Very young (1416/17) and after completing his elementary studies in Trebizond he moved to Constantinople, where he continued his studies at Crisoccocca and became a Basilian monk assuming the name of Bessarion, a saint of the fourth century.
In 1423 he went to Egypt. The next important stage was the years spent at Giorgio Gemisto Pletone in Mistra, near the ancient Sparta, in the despotate of Morea, where he was introduced to the Platonic philosophy (1430 / 2-1436). Paper-cutter and successful diplomat among the Byzantine courts, he soon obtained the esteem of Emperor John VIII Palaeologus.
In 1437 he was appointed archbishop of Nicea and in 1438 he came to Italy with cardinal Cusano, first in Ferrara, then in Florence, to discuss the union of the two churches together with the numerous Byzantine delegation and the emperor, in the hope of obtaining Western aid against the Ottomans who became increasingly threatening towards Constantinople.
While before the Council of Ferrara Bessarione belonged to the Byzantine party opposed to the union, during the Council it proved to be a proponent of the union of the Roman Church with the Orthodox one. On a philological and theological basis Bessarione demonstrated that a controversial passage in the text of Saint Basil (prominent figure of the Orthodox Church) supported positions equal to those of the Church of Rome, while copies of the text that did not have the offense were all very recent. The main dogmatic question that divided the two Churches was the one called the Filioque, concerning the relationship within the Trinity between the Son, the Father and the Holy Spirit: significant, in this regard, is the debate that, during the Council, occurred between Bessarione and Ludovico da Pirano, present as Bishop of Forlì. But the reasons that divided the two religions were more profound. The ecclesiological and historical-political reasons were so complex and profound that they seemed more difficult to overcome than the dogmatic ones.
This hostility of the Byzantines towards Latin Christians was understandable, given the presence of the latter in the Byzantine world, since the fourth crusade of 1204, which had destroyed the Byzantine Empire with the conquest and pillage of Constantinople and the division of Byzantine territories among the powers that had taken part in the "crusade", especially the Venetians. On 6 July 1439, however, and due to the explicit will of the Emperor to reach a compromise, the decree of the union of the Churches, from Cardinal Cesarini in Latin and from Bessarione, was read in the presence of Pope Eugene IV and the Emperor himself. in Greek.
Shortly after the Italian mission Bessarione returned to Constantinople. There he and the other proponents of the union found a hostile climate between the population and the clergy, especially the monks, while a part of those who had signed the decree of the union now abandoned it. Given this climate and the appointment as cardinal by Pope Eugenius IV on December 18, 1439, with the Title of the Saints XII Apostles, communicated to him while he was in Constantinople, Bessarione went back to Italy in 1440 from which he never returned to the Byzantine Empire. .
After a stay in Florence he went with the papal court to Rome.
In 1449 he changed his cardinal title with the suburban headquarters of Sabina-Poggio Mirteto, while maintaining the commend of the Title of the Saints XII Apostles. Soon after he opted for the suburban headquarters of Frascati, which he held until 1468, when he returned to that of Sabina, which he then held until his death.
Fallen Constantinople in 1453, he dedicated himself to rescuing the Byzantine scholars who had fled from the hands of the Ottomans. Between 1456 and 1465 it was Archimandrite of Messina and Baron of the Land of Savoca. In 1462 he was appointed first commendatory abbot of the Greek Abbey of Grottaferrata. Wanting to save the immense heritage of Byzantine culture collected numerous works that otherwise would never have come to the West, constituting a rich library, divided into two scripts, while still alive. In 1468 he donated his library to the city of Venice; the collection became the initial patrimony of the Marciana National Library. Among others, he saved numerous works contained in the rich library of the Monastery of San Nicola di Casole, near Otranto, which was then destroyed (by the Ottomans) during the Battle of Otranto in 1480.
In 1472 he was sent by Pope Sixtus IV to Louis XI of France to plead the cause of a crusade for the liberation of Constantinople, despite his age and his poor health. On the return journey, because of the inconvenience, his condition worsened and he died in Ravenna, in the house of a friend of his Venetian and mayor of the place, Antonio Dandolo, according to some poisoned on instigation of the French cardinals his opponents.
His body, moved to Rome on December 3 of the same year, was buried in the Basilica of the Holy XII Apostles.