These connections had been sufficient to open the Eastern ports to her trade, but her struggle with Carthage had left her no time or strength to interfere actively in Eastern politics, until she was forced to take action by the alliance of Philip V.of Macedonia and Hannibal, and by the former's threatened invasion of Italy in 214.

A small force was sent into Greece, which was soon largely increased by the dissatisfied subjects of Philip.
The only object of Rome in the First Macedonian War (214-205) was to prevent Philip from lending aid to Hannibal; and in this she was partially successful.

None of the Macedonian troops entered Italy, but four thousand of them were at Zama.
The military operations of this war were of slight importance.

Marcus Valerius Laevinus was sent to the Adriatic, and pushed the king so hard that he was obliged to burn the fleet in which he intended to sail for Italy.

Philip was at this time at war with Aetolia.