The First General Council of Lyon was presided over by Innocent IV. Innocent IV, threatened by Holy Roman Emperor Frederick II, arrived at Lyon December 2, 1244, and early in 1245 summoned the bishops and princes to the council. The chronicle of the Benedictine monastery of St. Peter at Erfurt states that two hundred and fifty prelates responded; the Latin Patriarchs of Constantinople, Antioch, and Aquileia (Venice), 140 bishops, the Latin emperor Baldwin II of Constantinople, Louis IX of France, Raymond VII, Count of Toulouse, and Raymond Bérenger IV, Count of Provence were among those who participiated. With Rome under siege by Emperor Frederick II, the pope used the council to excommunicate and depose the emperor, as well as the Portuguese King Sancho II. The council also directed a new crusade (the Seventh Crusade), under the command of Louis, against the Saracens and Mongols.
At the opening, June 28, Innocent IV preached his famous sermon on the five wounds of the Church enumerated his personal five sorrows: (1) the bad conduct of prelates and faithful; (2) the insolence of the Saracens; (3) the Greek Schism; (4) the cruelties of the Tatars in Hungary; (5) the persecution by the Emperor Frederick, who, not unexpectedly, did not appear.
At the second session (July 5) the bishop of Calvi and a Spanish archbishop attacked the emperor's manner of life and his plots against the Church, at the third (July 17), though Baldwin II, Raymond VII, and Berthold, Patriarch of Aquileia, interceded for Frederick, Innocent pronounced the deposition of Frederick, caused it to be signed by one hundred and fifty bishops and charged the Dominicans and Franciscans with its publication everywhere. But the pope lacked the material means to execute this decree; the Count of Savoy refused to allow an army sent by the pope against the emperor to pass through his territory, and for a time it was feared that Frederick would attack Innocent at Lyon.
The Council of Lyon took several other purely religious measures; it obliged the Cistercians to pay tithes, approved the Rule of the Order of Grandmont, decided the institution of the octave of the Nativity of the Blessed Virgin, prescribed that henceforth cardinals should wear a red hat, and lastly prepared thirty-eight constitutions which were later inserted by Boniface VIII in his Decretals, the most important of which, received with protests by the envoys of the English clergy, decreed a levy of a twentieth on every benefice for three years for the relief of the Holy Land (Constitution "Afflicti corde") and a levy for the benefit of the Latin Empire of Constantinople of half the revenue of benefices whose titulars did not reside therein for at least six months of the year (Constitution "Arduis mens occupata negotiis").