The Second Council of Lyon was the fourteenth ecumenical council of the Roman Catholic Church, convoked on 31 March 1272 and convened in Lyon, France, in 1274. Pope Gregory X presided over the council, called to act on a pledge by Byzantine emperor Michael VIII to reunite the Eastern church with the West. The council was attended by some bishops, sixty abbots and more than a thousand prelates or their procurators, among whom were the representatives of the universities. Due to the great number of attendees, those who had come to Lyon without being specifically summoned were given "leave to depart with the blessing of God" and of the Pope. Among others who attended the council were James I of Aragon, the ambassador of the Emperor Michael VIII Palaiologos with members of the Greek clergy and