The Romans overwhelmed him at Thermopylae in 191 BC. The battle of Thermopylae ended the Greek phase of the war between Rome and the Seleucid emperor Antiochus III.
In this war, Antiochus III was defeated in a battle against the consul Marcus Acilius and Cato, a general in that army. He was forced to flee back to Asia and his own territories were then invaded by the Romans, and the battle of Magnesia was finally brought to a close by the two Scipios.
The treaty of Apamea of 188 BC, took place after Roman victories in the battle of Thermopylae (191 BC), in the Battle of Magnesia (190) and after Roman and Rhodian naval victories over the Seleucid navy.
In this treaty Antiochus III had to abandon Europe altogether and all of Asia west of the Taurus. He was allowed to retain only twelves ships of war and required to pay a 15,000 talent indemnity, 500 immediately, 2,500 when the Romans government ratified the agreement, and thereafter 1,000 annually for 12 years.
Battle of Thermopylae (191 BC)
