During the Siege of Tunis in October 238 BC a rebel army under Mathos was besieged by a Carthaginian force under Hamilcar Barca and Hannibal. The Carthaginian army, which had served on Sicily during the First Punic War, mutinied in late 241 BC in the wake of Carthage's defeat, starting the Mercenary War. After three years of increasingly bitter war, the Carthaginians defeated the rebel field army at the Battle of the Saw, capturing its leaders. The Carthaginians then moved to besiege the rebels' strongest remaining stronghold at Tunis.