The Battle of Thermopylae took place on 24 April 191 BC. It was fought as part of the RomanâSeleucid War, pitting forces of the Roman Republic led by the consul Manius Acilius Glabrio against a Seleucid-Aetolian army of Antiochus III the Great.
When the main bodies of the armies initially clashed at the Thermopylae pass, the Seleucids managed to hold their ground, repulsing multiple Roman assaults. However, a small Roman force under Marcus Porcius Cato managed to outflank the Seleucids from the hillside after surprising the Aetolian garrison of Fort Callidromus. The Seleucids panicked and broke ranks, leading to the destruction of their force. Antiochus managed to escape the battlefield with his cavalry, departing mainland Greece soon afterwards.