Pope from 1243. Born of a family that produced another pope (Adrian V) and several cardinals, he was trained in canon and Roman law at Bologna where he also taught briefly. Confidant ofand made cardinal (1227), he succeeded Celestine IV after an eighteen-month vacancy owing to the pressure of Emperor . Innocent excommunicated him as had Gregory, and at the Council of Lyons* (1245) charged him with perjury and heresy. The intrigue between empire and papacy was alleviated with his death, but papal interference continued with his successors until an agreement was reached in 1254. Innocent’s Commentaria on canon law speaks defensively to the many extreme worldly entanglements he initiated and inherited.