War Begins: Rome Confronts Antiochus III in Greece

Antiochus III had returned from the east with the sheen of victory and the confidence of a restorer-king. By 196–194 BCE he was pressing claims along the Hellespont and in Thrace, and when he stepped into Greece in 192, he crossed an invisible line: Rome’s self-appointed guardianship of the post–Macedonian order [4][15][20]. The question was not one town or treaty. It was who would arbitrate Greek disputes and command the sea lanes from Euboea to Ephesus.

Rome answered with politics first. Senators convened allies in Pergamon and Rhodes, two powers whose fortunes rode on the same waters Antiochus courted. Eumenes II of Pergamon, a careful strategist, saw opportunity and peril in equal measure; Rhodian envoys, salt still in their tunics from the Aegean, argued that naval balance meant commercial freedom [2][4][15]. The stakes were Asia Minor’s harbors, the islands that dot the azure Aegean, and the tribute and trade that flowed through them.

Appian sketches the opening: embassies shuttled between Rome, Antioch, and Greek cities, while skirmishes of words hardened into preparations for war [4]. Livy’s eastern books—preserved in parts and in the Periochae—frame the Senate’s decision as a continuation of the policy that checked Philip V: intervene to prevent a hegemon, but leave the governing to allies [2][5][15]. The coalition would be the engine; Rome, the weight that made it move.

Three places mattered at once. At Corinth, Greek politics snapped and crackled like a dry olive fire as leagues counted spears. At Pergamon, Eumenes traced the coasts of Lydia and Caria with an ivory stylus, advising which cities might turn if the winds blew Roman. At Rhodes, shipwrights hammered planks until the sound carried across Mandraki harbor; the island’s future was built in the rhythmic creak of oarlocks [2][4][15].

The Senate’s intention was plain: compel Antiochus out of Greece, deny him the Aegean, and—if needed—carry the war to Asia. The means were sharper than the rhetoric. A Roman consular army would be paired with a fleet; allies would fill gaps in local knowledge and seamanship. The policy was a balance of power with teeth [2][4][15].

War, then, did not burst so much as assemble. Agreements in Rome, Pergamon, and Rhodes formed a lattice; Seleucid garrisons in Greece pressed against it. The collision would begin on the water near Corycus, then roll toward Ephesus and Sardis. But the opening move in 192 was a Roman decision about order. Antiochus had tested the limits. Rome meant to write them [2][4][15].