During 216 BCE the Macedonian king, Philip V, pledged his support to Hannibal – thus initiating the First Macedonian War against Rome in 215 BCE. The Romans were concerned that the Macedonians would attempt to cross the Strait of Otranto and land in Italy. They strongly reinforced their navy in the area and despatched a legion to stand guard, and the threat petered out. In 211 BCE Rome contained the Macedonians by allying with the Aetolian League, an anti-Macedonian coalition of Greek city states. In 205 BCE this war ended with a negotiated peace.