Antiochus III the Great (c. 241โ187 BC) was the 6th ruler of the Seleucid Empire. He assumed the throne at a young age when the empire was crumbling but spent most of his reign campaigning to restore its lost territories.
His 'Anabasis' to the East reasserted Seleucid authority over Parthia and Bactria, earning him the title 'The Great'. He then turned his attention west, challenging Roman influence in Greece.
However, his war against Rome ended in disaster. Defeated at Thermopylae and decisively at Magnesia (190 BC), he was forced to sign the Treaty of Apamea, which stripped the empire of its Anatolian territories and imposed a crippling war indemnity. He died while attempting to pillage a temple in Elymais to pay this debt.