 The Roman Senate had declared war on Carthage after Hannibal Barca had attacked, besieged and finally taken the city of Saguntum in Iberia in 219 BC.Rome had declared Saguntum an ally but had done nothing to help the city during the eight-month-long siege.Once the siege was over, the combatants started to make ready for the coming struggle, which was to last 18 years.