 In despair, the Carthaginians sued for peace but Regulus offered such harsh terms that the Carthaginians decided to fight on.Charge of the training of their army was given to the Spartan mercenary commander Xanthippus.In 255 BC Xanthippus led an army of 12,000 infantry, 4,000 cavalry and 100 elephants against the Romans and defeated them at the Battle of Tunis.