His very delay in the conclusion of the alliance with Hannibal damped the first and best zeal of the Greek patriots; and when he did enter into the conflict with Rome, his mode of conducting war was still less fitted to awaken sympathy and confidence.

His first attempt, which was made in the very year of the battle of Cannae (538), to obtain possession of the city of Apollonia, failed in a way almost ridiculous, for Philip turned back in all haste on receiving the totally groundless report that a Roman fleet was steering for the Adriatic.

This took place before there was a formal breach with Rome; when the breach at length ensued, friend and foe expected a Macedonian landing in Lower Italy.
Since 539 a Roman fleet and army had been stationed at Brundisium to meet it; Philip, who was without vessels of war, was constructing a flotilla of light Illyrian barks to convey his army across.

But when the endeavour had to be made in earnest, his courage failed to encounter the dreaded quinqueremes at sea; he broke the promise which he had given to his ally Hannibal to attempt a landing, and with the view of still doing something he resolved to make an attack on his own share of the spoil, the Roman possessions in Epirus (540).

Nothing would have come of this even at the best; but the Romans, who well knew that offensive was preferable to defensive protection, were by no means content to remain--as Philip may have hoped--spectators of the attack from the opposite shore.