In 219BC a Carthaginian army under Hannibal besieged, captured and sacked Saguntum and in spring 218BC Rome declared war on Carthage. There were three main military theatres in the war: Italy, where Hannibal defeated the Roman legions repeatedly, with occasional subsidiary campaigns in Sicily, Sardinia and Greece; Iberia, where Hasdrubal, a younger brother of Hannibal, defended the Carthaginian colonial cities with mixed success until moving into Italy; and Africa, where the war was decided.