In 1443, Eugene decided to take a neutral position on territorial disputes between Castile and Portugal and regarding rights claimed along the coast of Africa.

[2] He and several friends established a community of Canons Regular of San Giorgio in Alga in his native city in 1400, and received papal approval in November 1404.

By a written agreement made before his election, and ratified on 12 March 1431 as pope, Eugene pledged to distribute to the cardinals one-half of all the revenues of the Church and promised to consult with them on all questions of importance, both spiritual and temporal.

[12][13] Upon assuming the papal chair, Eugene IV took violent measures against the numerous Colonna relatives of his predecessor Martin V, who had rewarded them with castles and lands.

By far the most important feature of Eugene IV's pontificate was the great struggle between the Pope and the Council of Basel (1431–1439), the final embodiment of the Conciliar movement.

[16] Distrustful of its purposes and emboldened by the small attendance, the Pope issued a bull on 18 December 1431 that dissolved the council and called a new one to meet in eighteen months at Bologna.

[20] On 4 June 1434, disguised in the robes of a Benedictine monk, Eugene was rowed down the center of the Tiber, pelted by stones from either bank, to a Florentine vessel waiting to receive him at Ostia.

Traditional Papal enemies such as the Prefetti di Vico were destroyed, while the Colonna were reduced to obedience after the destruction of their stronghold in Palestrina in 1437.

[27] Poggio Bracciolini, the Tuscan humanist, wrote: "Seldom has the rule of any other pope produced equal devastation in the provinces of the Roman Church.

Eugene IV at length convened a rival council at Ferrara on 8 January 1438, through his legate Cardinal Niccolò Albergati, Bishop of Bologna, with forty prelates in attendance.

Mandell Creighton remarks, "The quarrel of the Pope and the Council now ceased to attract the attention of Europe; it had degenerated into a squabble in which both parties were regarded with something approaching contempt.

[43] A union with the Eastern Orthodox Church was effected on 6 July 1439, with the bull "Laetentur caeli",[44] which, as the result of political necessities, proved but a temporary bolster to the papacy's prestige.

[46][14] He did his best to stem the Turkish advance, pledging one-fifth of the papal income to a crusade which set out in 1443, but which met with overwhelming defeat at the Battle of Varna.

One of the king's ablest advisers, the humanist Aeneas Sylvius Piccolomini, who was later to be Pope Pius II, made peace with Eugene in 1442.

The Pope's recognition of the claim to Naples of King Alfonso V of Aragon (in the treaty of Terracina, approved by Eugene at Siena somewhat later) withdrew the last important support in Italy from the Council of Basel.

"[49] His protests against the Pragmatic Sanction of Bourges were ineffectual, but by means of the Concordat of the Princes, negotiated by Aeneas Silvius Piccolomini, the secretary of Frederick III, with the electors in February 1447, the whole of Germany declared against the antipope.

Eugene condemned the enslavement of the peoples of the newly colonized Canary Islands and, under pain of excommunication, ordered all such slaves to be immediately set free.

[56] Eugene went on to say that, "If this is not done when the fifteen days have passed, they incur the sentence of excommunication by the act itself, from which they cannot be absolved, except at the point of death, even by the Holy See, or by any Spanish bishop, or by the aforementioned Ferdinand, unless they have first given freedom to these captive persons and restored their goods."

Eugene tempered "Sicut Dudum" in September 1436 with the issuance of a papal bull in response to complaints made by King Edward of Portugal that allowed the Portuguese to conquer any unconverted parts of the Canary Islands.

On 19 December 1442, Eugene replied by issuing the bull Illius qui se pro divini,[58] in which he granted full remission of sins to members of the Order of Christ and those enrolled under their banner who took part in any expeditions against the Saracens and enemies of Christianity.

[59] In 1443, in the bull "Rex regum", the Pope took a neutral position on territorial disputes between Portugal and Castile regarding rights claimed in Africa.

[60] Richard Raiswell interprets the bulls of Eugene as helping in some way the development of thought which perceived the enslavement of Africans by the Portuguese and later Europeans "as dealing a blow for Christendom".

[61] Joel S Panzer views Sicut Dudum as a significant condemnation of slavery, issued sixty years before the Europeans found the New World.

[62] Although his pontificate had been so stormy and unhappy that he is said to have regretted on his deathbed that he ever left his monastery,[14][63] Eugene IV's victory over the Council of Basel and his efforts on behalf of church unity nevertheless contributed greatly to the breakdown of the conciliar movement and restored the papacy to a semblance of the dominant position it had held before the Western Schism (1378–1417).