Aetolian War participant Aetolian League
Thermopylae
The spring of 191 BC saw the Macedonians enter the war against the Aetolian League – they operated independently of the Romans – and occupy a number of towns in Thessaly. Antiochus moved on Acarnania, but was forced to withdraw when he heard of the incursion into Thessaly. By the time the consul Glabrio reached Thessaly, towns simply surrendered without a fight. Antiochus, receiving no reinforcements and heavily outnumbered by the Roman coalition, was forced to choose between retreat or doing battle where the coalition's numerical superiority would be minimised. He chose Thermopylae. The resulting battle was such an overwhelming defeat for Antiochus that he immediately fled Greece for Ephesus. Less than six months had elapsed from his arrival in Demetrias. With the Roman victory there, the Greek cities that sat on the sidelines quickly flocked to join the victors.Glabrio turned his eye towards the Aetolians and captured Heraclea that year before besieging Naupactus after peace negotiations – the Aetolian ambassadors sought to surrender but the specific rites for surrender were unclear and vitiated by their need for ratification – fell apart. Succeeded by the consul of 190 BC, Lucius Cornelius Scipio and Lucius' able legate Scipio Africanus, Glabrio returned to Rome and celebrated a triumph. That year, the Roman fleet under Gaius Livius won a battle off Corcyra forcing Antiochus' fleet to retreat to Ephesus; Antiochus then dispatched fleet reinforcements from Syria under the command of Hannibal, who had years previously fled to Antiochus' court.Prevented from crossing the Aegean directly, the Scipios stayed in Europe, where they oversaw a six-month truce with the Aetolians so that they could send envoys to the senate in Rome negotiate a peace. In the meantime, the Scipios marched on the land route for Asia Minor. Fortunately for the Romans, Hannibal's fleet was stopped by the Rhodians at the Battle of the Eurymedon and the remaining fleet at Ephesus was destroyed by Livius' successor, Lucius Aemilius Regillus, in the Battle of Myonessus. Aemilius' victory forced Antiochus to withdraw in haste back across the Hellespont to Asia Minor. When the Romans advanced into Thrace, Antiochus' allies did nothing to stop them; when they crossed the Hellespont, he gave no contest.