Basel, Council of, 1431–49, first part of the 17th ecumenical council in the Roman Catholic Church. It is generally considered to have been ecumenical until it fell into heresy in 1437; after that it is regarded as an anticouncil. Its chief importance lies in the contest between council and pope for supremacy.
The Council of Constance had seen the rise of the conciliar theory, the doctrine that the ultimate authority in the church rests upon the general council, to which the pope must be subject. It had been the plan to have frequent councils, but that of Basel was the first of importance to follow Constance, that of Pavia-Siena (1423–24) having accomplished little. Pope Martin V convoked the council but died soon afterward, and it was his successor, Eugene IV, who confirmed the convocation.
Various problems were brought before the council: the settlement of the difficulties with the Hussites; reform in the church, particularly financial reform; and the matter of negotiations for the union of the Eastern church and the Western church. Even though he had convened it, Eugene was suspicious of the council, fearing that in the question of the Hussites it might reawaken doctrinal questions already regarded as settled. Therefore, he ordered the council dissolved almost immediately. This marked the outbreak of trouble between the council and the pope that was not to end until the council did.
Holy Roman Emperor Sigismund, who desired the settlement of Hussite disputes from the council and desired coronation at the hands of the pope, acted as mediator. The council pronounced its supremacy over the pope and in 1433 reached the zenith of its power. Fearing schism, Eugene was driven to grant more and more concessions, but any compromise reached was temporary. The continual assertion of the conciliar supremacy led to the institution of a process against the pope for disobedience and ultimately to the papal denunciation of the council in the bull Doctoris gentium (1437).
The council, which thus became heretical, had accomplished a good deal. The Compactata had marked a compromise with the Hussites; the annates and various papal taxes had been declared illegal; church organization and finance had been reformed.
In order to meet with delegates from the East on the question of reunion, Eugene summoned the council to Ferrara (see Ferrara-Florence, Council of). The council at Basel continued to function as an anticouncil. Finally the process against Eugene was carried through, and the council elected Amadeus VIII of Savoy pope (called Pope Felix V; regarded by opponents as antipope). The allegiance of most temporal rulers was still given to Eugene; although the reforms of Basel were adopted by the French at Bourges and incorporated into the Pragmatic Sanction of Bourges, the council was not itself approved. The German king Frederick III (who was later crowned Holy Roman emperor) remained neutral, but in 1448 his pressure on the city forced the delegates to retire to Lausanne. Felix, with only scattered support, abdicated in 1449, submitting to Eugene's successor, Nicholas V. The council recognized the legitimate pope and dissolved itself, thus ending the threat of antipapal conciliarism.