Aetolian War participant Ancient Rome
The Roman–Seleucid war (192–188 BC), also called the Aetolian war, Antiochene war, Syrian war, and Syrian-Aetolian war was a military conflict between two coalitions, one led by the Roman Republic and the other led by the Seleucid king Antiochus III. The fighting took place in modern-day southern Greece, the Aegean Sea, and Asia Minor.
The war was the consequence of a "cold war" between both powers, which had started in 196 BC. In this period, the Romans and the Seleucids attempted to settle spheres of influence by forging alliances with the small Greek city-states. Also important were the Romans and Seleucids' irreconcilable visions for the Aegean: the Romans saw Greece as their sphere of influence and Asia Minor as a buffer area while the Seleucids saw Asia Minor as a core part of their empire with Greece as the buffer zone.
After the Aetolian League triggered a small war which drew in Antiochus, Rome and the Seleucids came to blows. Antiochus' landed in Greece but was forced to retreat across the Aegean after being defeated at the Battle of Thermopylae by the consul of 191 BC, Manius Acilius Glabrio. The Aetolians attempted to reach a settlement with the Romans but were unsuccessful in the face of maximalist Roman demands. Antiochus' naval forces in the Aegean were defeated in two major engagements which saw the Roman coalition gain naval superiority. The consul of 190 BC, Lucius Cornelius Scipio, then pursued Antiochus into Asia Minor with the support of the Pergamene king Eumenes II.
Antiochus started peace negotiations, which he broke off after maximalist Roman demands. But after he was defeated by the Roman-led coalition at the Battle of Magnesia, he sued for peace, accepting those Roman demands. In the resulting peace of Apamea, Antiochus ceded all of his territories beyond the Taurus mountains to Roman allies and paid a large indemnity covering the Roman cost of the war. The Aetolians reached separate terms with the Romans, reducing them to a Roman client state, the next year. The Romans thereby gained uncontested hegemony over the Greek city-states in the Balkans and Asia Minor while also largely excluding the Seleucids from the Mediterranean.