Sicily remained firmly in Roman hands, blocking the ready seaborne reinforcement and resupply of Hannibal from Carthage. Hiero II, the old tyrant of Syracuse of forty-five-years standing and a staunch Roman ally, died in 215BC and his successor Hieronymus was discontented with his situation. Hannibal negotiated a treaty whereby Syracuse came over to Carthage, at the price of making the whole of Sicily a Syracusan possession. The Syracusan army proved no match for the Romans, and by spring 213BC Syracuse was besieged. Both Polybius' and Livy's accounts of the siege focus on Archimedes' invention of war machines to counteract Roman siege warfare, made more difficult by the strong defenses of the city.