After having won control of the seas, a Roman force landed on the African coast under Marcus Regulus, who was at first victorious, winning the Battle of Adys and forcing Carthage to sue for peace. However, the terms of peace that Rome proposed were so heavy that negotiations failed, and in response, the Carthaginians hired Xanthippus of Carthage, a mercenary from the martial Greek city-state of Sparta, to reorganise and lead their army. Xanthippus managed to cut off the Roman army from its base by re-establishing Carthaginian naval supremacy and then defeated and captured Regulus at the Battle of Tunis.