The first council of Lyons, in 1245, was convened by Innocent IV, who had fled Rome for a city outside imperial reach, and its principal business was the deposition of the emperor Frederick II, pronounced with the bishops holding lighted candles that they then threw to the ground. It also gave cardinals the red hat and legislated for a crusade. The second, in 1274, was larger and more ambitious: it enacted the rules for papal conclaves that still govern the enclosure of the electors, and it proclaimed a union with the Greek church negotiated with the emperor Michael VIII, whose delegates accepted the Roman claims on his behalf.
The union collapsed within a decade because the Byzantine clergy and people would not have it, and Michael was denied burial rites by his own church. Thomas Aquinas died on the road to that council and Bonaventure died during it. A century before either, the city had produced a movement of a different kind: a merchant called Valdes gave away his property in about 1173, had parts of the scriptures put into the local speech, and began to preach. Forbidden to preach without licence, his followers went on, were excommunicated, and became the Waldensians, who survived in the alpine valleys and eventually joined the Reformation.