FILLASTRE, GUILLAUME. — Born at La Suze (Maine) around 1348. He studied law, became a priest, and was a celebrated orator. Dean of Reims in 1392. He revealed his personality at the Synod of Paris in 1406, where he defended the antipope Benedict XIII against the representatives of the king and the university, maintaining that princes had no right to judge matters of the Church and that general councils were not above the Pope.
At the time of the Council of Pisa (1409), he broke with Benedict XIII, together with D’Ailly, and was one of the supporters of the other antipope, John XXIII, who created him cardinal on 6 June 1411. At the Council of Constance, in which he played a leading role, he sided against John XXIII and, contrary to the opinions vigorously asserted at the Parisian Synod of 1406, upheld the superiority of the council over the Pope. He succeeded in having the assembly approve the five famous articles, after reconciling the cardinals with the Emperor Sigismund. He did not take part in the trials of Huss and Petit because he was ill. He returned to the Council in 1417 and was charged with securing the resignation of the recalcitrant Benedict XIII; he fulfilled this task, and at the 37th session, on 26 July 1417, he himself read the conciliar sentence deposing the antipope Benedict. He played a very active part in the Conclave from which Martin V was elected; the latter entrusted him with various diplomatic missions in France and appointed him archpriest of St. John Lateran. He died in Rome on 6 November 1428.
The fame of F., besides his ecclesiastical policy, is linked to the works he left in manuscript. His sermons are of the greatest importance. He wrote on theology and law, science and geography, and prepared a very detailed account of the Council of Constance. Although various accusations were brought against him—such as his change of allegiance regarding John XXIII, who had created him cardinal, and his abandonment of opinions, theologically irreproachable, which he had expressed at the Parisian Synod—he is nevertheless excused by his good intentions in seeking a way out that might bring the schism to an end.