Thirteenth Ecumenical Council: Lyons I (1245)

The First General Council of Lyons was presided over by Innocent IV; the Patriarchs of Constantinople, Antioch, and Aquileia (Venice), 140 bishops, Baldwin II, Emperor of the East, and St. Louis, King of France, assisted. It excommunicated and deposed Emperor Frederick II and directed a new crusade, under the command of St. Louis, against the Saracens and Mongols.