Stephen was originally a priest at the Church of Saints Sylvester and Martin, but in 939 he was elected as pope. His first action was to mediate between the rebellious Count Herbert II of Vermandois and Hugh the Great and King Louis IV of France, who was trying to bring them to heel. The Frankish bishops backing the rebels backed off, but Stephen had his own problems when Hugh of Arles besieged Rome in 940 in hopes of overthrowing Alberic II of Spoleto, the effective ruler of Rome. He failed to assassinate Alberic, who retaliated by cracking down on his enemies. Stephen was maimed, and died in 942.