GIOVANNI VIII Paleologo, EMPEROR of BYZANTIUM. — Son of Manuele II Paleologo, born in 1383, co-emperor with his father, he succeeded him in 1425.
The Byzantine Empire had by then been reduced to the capital alone and to a few territories in Thrace and Morea. G. VIII had opposed his father’s tendencies, who desired agreements with the Turkish sultan, and had insisted on a vigorous policy. Yet resisting Murad’s enormous superiority was absurd. G. VIII attempted the only course that offered hope: finding military aid in the West with the support of the papacy. To this end, he revived the project of union between the Churches and began negotiations with Martino V and Eugenio IV, offering to convene a council at Constantinople. Rome opposed this proposal, calling instead for a council in the West.
The discussion became more complicated when the conflict arose between the Roman Curia and the Council of Basel, which negotiated separately with the Byzantine Emperor. The latter hoped to reach an agreement with the Fathers of Basel, thereby avoiding the thorny question of papal supremacy, which was distasteful to the Greeks and disputed at Basel. The victory of Eugenio IV and the convocation of the Council of Ferrara (18 January 1438) determined G. VIII’s course: he came to Italy with the Byzantine patriarch and the delegation of Greek theologians. The negotiations at Ferrara were transferred to Florence, where the Council was moved in 1439. To facilitate agreement, public discussions were abandoned and the question of union was entrusted to commissions; G. VIII, concerned to preserve the union, silenced the anti-unionists. The question of papal authority was overcome through the vague formula proposed by the patriarch of Nicaea Bessarione. The conciliar proceedings ended on 5 July 1439, and on the 6th the union was proclaimed in the Florentine Cathedral. G. VIII did not return to his capital until February 1440, but the clergy’s violent opposition to his actions prevented the union, which was not proclaimed in S. Sofia. Urged on by the Pope, the Emperor attempted to replace the most hostile ecclesiastical dignitaries and organized public discussions to popularize the matter, but achieved nothing.
The crusade projects discussed at Florence came to nothing; the attempts of Giovanni Hunyadi and the Venetians met with indifference at Constantinople. The most serious question was now the succession to the throne: among G. VIII’s brothers, Costantino and Teodoro were unionists, whereas Demetrio was hostile; in 1442 he had already rebelled, and the sultan Murad intervened as peacemaker in the civil war. G. VIII died on 31 October 1448.