The second council of Lyon is a Concile Catholique which was held with Lyon in 1274. It was chaired by the pope Gregoire {{X}}, bringing together approximately five hundred bishops, sixty abbots and more than thousand prelates. The first session opened May 7th 1274, with five additional sessions the May 18th, June 7th, July 6th, July 16th and July 17th. Jacques {{Ier}} of Aragon, the ambassador of the emperor Michel Paleologist and the members of the Greek clergy and the ambassadors of the Khan of the Tatar were present.

The main subjects were:

• the conquest of the Holy Land,
• union of the churches of the East and Occident,
• the pontifical election.

Thomas d' Aquin had been convened with the council, but died on the way in Fossanova. Bonaventure de Bagnorea was present at the first four sessions, but died in Lyon on July 15th.

Reconquest of the Holy Land

The council deliberated on the financial aspects of the Croisade. It was decided that during six years the Dîme of all the benefit of Christendom should return to the crusade. Jacques 1st of Aragon wished to organize forwarding immediately, but the Templiers were opposed to it. The ambassadors of Khan of Tatars were in talks with the pope, who wished that they leave the Christians in peace during the war against the Islam. It is finally a local lord, Guillaume of Roussillon, lord of Annonay, which was indicated by the king of France Philippe III the Bold one. It took the head of a troop of 100 riders and 400 infantrymen.

Union of the Churches

Wishing to finish some with the Schism between Rome and Constantinople, thousand-year-old Gregoire Ve front J. - C. had sent an embassy to Michel Paléologue and had required of the Latin chiefs in the east to limit their ambitions. The patriarch of Constantinople Germanus and other Eastern dignitaries arrived at Lyon on June 24th, presenting a letter of the emperor. June 29th, Gregoire {{X}} celebrated the Messe in the Midsummer's Day church, where the two parties took seat. The Greeks read the Symbole of Nicée, with the discussed Western addition of the Filioque, sung three times. The council was apparently a success, but did not provide a durable solution to the schism.

Other discussed subjects

The council treated reform of the Church. Several bishops and abbots were deposited for unworthiness, and some orders beggars were removed. In addition, the two new orders of the Dominican S and the Franciscain S were approved.

As several long holidays ago of the the Holy See, the council decided that the cardinal should not leave the Conclave as long as a pope would not be elected. This decision was suspended in 1276 by the pope Adrien {{V}}, then withdrawn by the pope Jean {{XXI}}. Since was restored it, and is at the base of the current legislation of the papal election.

The council regulates the office of ecclesiastical lawyer.

Finally the council treated the imperial throne, that Jacques 1st of Aragon claimed. It was deposed by the pope, and Rodolphe {{Ier}} was proclaimed king of the Romans and future emperor on June 6th.