In 193 BC, Scipio was one of the commissioners sent to Africa to settle a dispute between Massinissa and the Carthaginians, which the commission did not achieve. This may have been because Hannibal, in the service of Antiochus III of Syria, might have come to Carthage to gather support for a new attack on Italy. In 190 BC, when the Romans declared war against Antiochus III, Publius offered to join his brother Lucius Cornelius Scipio Asiaticus if the Senate entrusted the chief command to him. The two brothers brought the war to a conclusion by a decisive victory at Magnesia in the same year.