Hellenistic period Balkans, Philip allied himself with Carthage after Hannibal had dealt the Romans a massive defeat at the Battle of Cannae (216 BC) during the Second Punic War. Forcing the Romans to fight on another front when they were at a nadir of manpower gained Philip the lasting enmity of the Romans—the only real result from the somewhat insubstantial First Macedonian War (215–202 BC). Once the Second Punic War had been resolved, and the Romans had begun to regather their strength, they looked to re-assert their influence in the Balkans, and to curb the expansion of Philip. A pretext for war
History of Macedonia (ancient kingdom) of the Italian peninsula. In 216 BC, Philip V sent a hundred light warships into the Adriatic Sea to attack Illyria, a motion that did not go unnoticed by Rome when Scerdilaidas of the Ardiaean Kingdom appealed to the Romans for aid. Rome responded by sending ten heavy quinqueremes from Roman Sicily to patrol the Illyrian coasts, causing Philip V to reverse course and order his fleet to retreat, averting open conflict for the time being. In 215 BC, at the height of the Second Punic War with the Carthaginian Empire, Roman authorities intercepted a ship off the Calabrian coast