Rome's preoccupation with its war with Carthage provided an opportunity for Philip V of the kingdom of Macedon in northern Greece to attempt to extend his power westward. Philip sent ambassadors to Hannibal's camp in Italy, to negotiate an alliance as common enemies of Rome. However, Rome discovered the agreement when Philip's emissaries, along with emissaries from Hannibal, were captured by a Roman fleet. Desiring to prevent Philip from aiding Carthage in Italy and elsewhere, Rome sought out land allies in Greece to fight a proxy war against Macedon on its behalf and found partners in the Aetolian League of Greek city-states, the Illyrians to the north of Macedon and the kingdom of Pergamon and the city-state of Rhodes, which lay across the Aegean from Macedon.