The First Council of Lyon was the thirteenth ecumenical council of the Catholic Church, taking place in southern France in 1245 AD. It was presided over by Pope Innocent IV, who was threatened by the Holy Roman Emperor Frederick II, , and early the following year he summoned the Church's bishops to the council later that same year. Some two hundred and fifty prelates responded including the Latin Patriarchs of Constantinople, Antioch, and Aquileia, as well as 140 bishops. With Rome under siege by Emperor Frederick II, the pope used the council to excommunicate and depose the emperor with Ad Apostolicae Dignitatis Apicem, as well as the Portuguese King Sancho II. The council also directed a new crusade (the Seventh Crusade), under the command of Louis IX of France, to reconquer the Holy Land.
