The siege of Syracuse by the Carthaginians from 311 to 309 BC followed shortly after the Battle of the Himera River in the same year. In that battle the Carthaginians, under the leadership of Hamilcar the son of Gisco, had defeated the tyrant of Syracuse, Agathocles. Agathocles had to retreat to Syracuse and lost control over the other Greek cities on Sicily, who went over to the Carthaginian side.