Fearing that Antiochus would seize the entirety of Asia Minor, the independent cities Smyrna and Lampsacus decided to appeal for protection from the Roman Republic.

[4] In the early spring of 196 BC, Antiochus' troops crossed to the European side of the Hellespont and began rebuilding the strategically important city of Lysimachia.

[5] In late winter of 196/195 BC, Rome's erstwhile chief enemy, Carthaginian general Hannibal, fled from Carthage to Antiochus' court in Ephesus after his homeland became a Roman client state.

[6] The Aetolians began spurring Greek states to jointly revolt under Antiochus' leadership against the Romans, hoping to provoke a war between the two parties.

The Aetolians then captured the strategically important port city of Demetrias, killing the key members of the local pro-Roman faction.

On 26 April 191 BC, the two sides faced off at the Battle of Thermopylae, Antiochus' army suffered a devastating defeat and he returned to Ephesus shortly afterwards.

[11] The Romans intended to invade the Seleucid base of operations in Asia Minor which could only be done by crossing the Aegean Sea, the Hellespont being the preferable option due to logistical concerns.

[12] A Roman naval force under Gaius Livius Salinator consisting of 81 ships arrived at Piraeus too late to impact the campaign in mainland Greece.

After returning to Ephesus, Antiochus transferred most of his navy to the Hellespont, simultaneously ordering Admiral Polyxenidas to build a new fleet for the protection of the Asia Minor coastline.

According to Livy’s Ab Urbe Condita Libri the Romans were confined to the harbor by Etesian winds; British historian John Graigner on the other hand argued that Livius and Pergamene King Eumenes II who accompanied him were busy establishing diplomatic and military contacts.

[14] In September 191 BC, Antiochus entrusted Polyxenidas with a fleet of 70 decked tectae and 100 to 130 apertae (merchant galleys capable of fighting[15]).

[17] The allied fleet sailed to Phanai in southern Chios and from there to its main harbor to obtain supplies, while the Rhodians had just reached Samos.

At Phocaea, Polyxenidas recognized the risk of the allies could first unite with the Rhodian navy as well as the fact one could reach Elaea undetected from the side of Lesbos.

[21] When the battle lines closed, the Romans used grappling hooks to board the Seleucid ships and overwhelm their smaller crews with marine infantry.

[20] In 190 BC, Antiochus ordered Hannibal to build a new fleet in Cilicia, his first major military command after spending five years in the Seleucid court.