Louis IX decided to support Charles' military campaign in Italy in May 1263. Pope Urban IV promised to proclaim a crusade against Manfred, while Charles pledged that he would not accept any offices in the Italian towns. Manfred staged a coup in Rome, but the Guelphs elected Charles senator (or the head of the civil government of Rome). He accepted the office, at which a group of cardinals requested that the Pope revoke the agreement with him, but the Pope, being otherwise defenceless against Manfred, could not break with Charles.