In 196 BCE, the Romans, victorious in the Battle of Cynoscephalae over Philip V in the previous year, took possession of Demetrias and garrisoned the town. Four years later the Aetolian League captured it by surprise. The Aetolians allied themselves with Antiochus III of the Seleucid Empire in the Roman–Seleucid War. This ended in the defeat of Antiochus. After the return of Antiochus to Asia in 191 BCE, Demetrias surrendered to Philip, who was allowed by the Romans to retain possession of the place. It continued in the hands of Philip and his successor till the over-throw of the Macedonian monarchy at the Battle of Pydna, 169 BCE.