First Council of Lyon

Since the great majority of those bishops and archbishops present came from France, Italy and Spain, while the Byzantine Greeks and the other countries, especially Germany, were but weakly represented, the ambassador of Frederick, Thaddaeus of Suessa, contested its ecumenicity in the assembly itself.

In the bull Cum simus super (25 March 1245), he also urged the Vlachs, Serbs, Alans, Georgians, Nubians, the Church of the East and all the other Eastern Christians not in union with Rome to send representatives.

In the end, the only known non-Latin cleric present was Peter, the bishop of Belgorod and vicar of the metropolitanate of Kiev, who provided Innocent with intelligence on the Mongols prior to the council.

The objections of the ambassador, that the accused had not been regularly cited, that the pope was plaintiff and judge in one, and that therefore the whole process was anomalous, achieved as little success as his appeal to the future pontiff and to a truly ecumenical council.

The Council of Lyon promulgated several other purely disciplinary measures: Among those attending was Thomas Cantilupe who was made a papal chaplain and given a dispensation to hold his benefices in plurality.