CONCILIARISM. — Ecclesiological error according to which an ecumenical council is superior to the pope. The remote origin of conciliarism is found in the juridical principle (Decretum of Gratian, dist. XL, c. 6) according to which the pope can be judged by the Church in case of heresy. This maxim, which is encountered throughout the Middle Ages, spread the idea that there were cases in which the pope could be subject to judgment by his subjects. When, at the end of the 13th century and the beginning of the 14th, the struggles of Boniface VIII with Philip the Fair and of John XXII with Louis of Bavaria shook the authority and prestige of the Roman pontiff in the minds of many, the old principle was invoked and amplified: not only in the case of heresy, but also when in the exercise of his power he oversteps his bounds, the pope can be called to order; precisely at that time appeals to the council became frequent.
It was in this climate that Marsilius of Padua’s Defensor pacis (v.) was born, according to which Jesus Christ did not establish on earth any vicar of His who would be the head of the Church, since all ministers of religion have equal powers; the papacy is a creation of the emperor, who can correct and depose the holders of the tiara; the supreme organ of ecclesiastical governance is not the papacy, but the ecumenical council, convoked by imperial authority and composed not only of bishops and priests, but also of laymen; its decrees come immediately after Scripture and before papal decrees and have full force by virtue of imperial power. If the ecumenical council preserves for the pope the directive power that, due to a complex of circumstances, was entrusted in the past to the bishop of Rome, this does not mean that such a mandate cannot be revoked.
Despite the condemnation by John XXII, these errors, sponsored and amplified (e.g., denial of infallibility) by the rebellious Franciscan William of Ockham (v.), spread widely, especially in Bavaria. When the Western Schism (1378–1417) afflicted the Church, many, even those well-intentioned, found in these theories a way out of so many evils. Precisely at the beginning of the schism, two German doctors of the University of Paris systematized conciliar doctrine: Conrad of Gelnhausen and Henry of Langenstein. The former published in 1380 an Epistola concordiae, the latter in 1379 an Epistola pacis, in which the necessity of an ecumenical council is urged and a broad plan of reform is proposed; but while Conrad attributes supreme power to the assembled bishops, Henry sees its origin in the collectivity of the faithful. These theories would receive further development in Peter d’Ailly (1350–1420), a brilliant doctor and chancellor of the University of Paris. A convinced Ockhamist in several doctrinal points, as early as 1380 he gave voice to the doubts that, amid so much turmoil, had disturbed the best minds. It is unlikely, he said, that the Lord founded the firmness of the Church on Peter’s weakness, since Peter and his successors have erred so often; one must therefore hold that the Church is founded on Jesus Christ and that the pope is not essential to it; hence every power descends directly from God to the bishops and priests, who, assembled in council, constitute the supreme authority of the Church, and thus superior to the pope. The pope can be said to be head of the Church only in a ministerial and administrative capacity, and since he can err and even fall into heresy, he must in such a case be corrected and even deposed. Only the universal Church is infallible, in the sense that even if the entire clergy should fall into error, there will always be some simple soul and some pious layman who will preserve the deposit of Revelation. Such were the ideas of the abbot-chancellor, who soon became archbishop of Cambrai (1397) and a cardinal of Avignon (1411) and one of the presidents of the Council of Constance. Gerson (v.), who went further than his master. While Peter d’Ailly, developing the ideas of Conrad of Gelnhausen, conceived of the Church as an episcopal aristocracy, Gerson, following the line traced by Henry of Langenstein, became an advocate first of a tempered democracy (parish priests have a decisive vote in the council along with bishops, since both are of divine origin), then fell into multitudinarianism, teaching that the entire mystical body of the faithful has equal rights in ecclesiastical governance, which it nevertheless transmits to the bishops and the pope. Hence the logical deduction that the ecumenical council, and even the entire community, can call the pope to duty and, if necessary, depose him.
Gerson, however, a truly pious man, was better in his conduct than in his ideas. Meanwhile, these ideas, under the aegis of so great a man, spread and were practically applied in the Councils of Constance and Basel, and while they penetrated the minds of many writers, they fostered the development of contemporary heresies (Wycliffe of Hils) and subsequent ones (Lutheranism, Calvinism, Anglicanism), only to take refuge, after the Council of Trent, among those French Catholics who, in the name of Gallican liberties (v. GALLICANISM), opposed for centuries the free exercise of papal authority. The error lived on even into the Vatican Council, where, however, it received its death blow (Denz.-U., 1830).