Guillaume Fillastre

Antipope John XXIII conferred on him and his friend Pierre d'Ailly the dignity of cardinal (1411), and in 1413 he was made Archbishop of Aix.

Fillastre took a very important part in the Council of Constance, where he and Cardinal d'Ailly were the first to agitate the question of the abdication of the rival claimants (February, 1415).

During the Council of Constance Fillastre kept a diary discovered by Heinrich Finke, first reviewed by him in the Römische Quartalschrift (1887), and there partly edited by him.

Fillastre is our only authority concerning the preliminary motions on the method of voting and the extremely difficult position of the college of Cardinals; he gives us our first clear conception of the quarrels that arose among the "nations" over the matter of precedence, and the place which the Spanish "nation" held at the council; he also furnishes the long-sought explanation of the confirmation of Sigismund as Holy Roman Emperor by Martin V. Fillastre's diary derives its highest value, however, from the exposition of the relations between the king and the council and the description of the conclave.

Thus he had copied the Latin translation of Ptolemy's geography (without maps), which had been completed by Jacopo d'Angelo in 1409, a manuscript he had great difficulty in securing from Florence.

The two geographical codices are reportedly still preserved as precious "cimelia" in the municipal library of Reims, but the map of the world disappeared during the eighteenth century.