Antiochus III the Great

Antiochus III the Great, (c. 241–187 BC, ruled 223–187 BC), younger son of Seleucus II Callinicus, became ruler of the Seleucid kingdom as a youth of about eighteen in 223 BC. His traditional designation, the Great, stems from a misconception of Megas Basileus (Great king), the traditional title of the Persian kings, which he adopted.

Antiochus III inherited a disorganized state. Not only had Asia Minor become detached, but the further eastern provinces had broken away, Bactria under the Greek Diodotus of Bactria, and Parthia under the nomad chieftain Arsaces. Soon after Antiochus's accession, Media and Persis revolted under their governors, the brothers Molon and Alexander.

The young king, under the baneful influence of the minister Hermeias, authorised an attack on Judea instead of going in person to face the rebels. The attack on Judea proved a fiasco, and the generals sent against Molon and Alexander met with disaster. Only in Asia Minor, where the king's cousin, the able Achaeus represented the Seleucid cause, did its prestige recover, driving the Pergamene power back to its earlier limits.

In 221 BC Antiochus at last went east, and the rebellion of Molon and Alexander collapsed. The submission of Lesser Media, which had asserted its independence under Artabazanes, followed. Antiochus rid himself of Hermeias by assassination and returned to Syria (220 BC). Meanwhile Achaeus himself had revolted and assumed the title of king in Asia Minor. Since, however, his power was not well enough grounded to allow of his attacking Syria, Antiochus considered that he might leave Achaeus for the present and renew his attempt on Judea.

The campaigns of 219 BC and 218 BC carried the Seleucid arms almost to the confines of Egypt, but in 217 BC Ptolemy IV confronted Antiochus at the battle of Raphia and inflicted a defeat upon him which nullified all Antiochus's successes and compelled him to withdraw north of the Lebanon. In 216 BC Antiochus went north to deal with Achaeus, and had by 214 BC driven him from the field into Sardis. Antiochus contrived to get possession of the person of Achaeus (see Polybius), but the citadel held out until 213 BC under Achaeus' widow Laodice and then surrendered.

Having thus recovered the central part of Asia Minor — for the Seleucid government had perforce to tolerate the dynasties in Pergamon, Bithynia and Cappadocia — Antiochus turned to recover the outlying provinces of the north and east. He obliged Xerxes of Armenia to acknowledge his supremacy in 212 BC. In 209 BC Antiochus invaded Parthia, occupied the capital Hecatompylus and pushed forward into Hyrcania. The Parthian king Arsaces II apparently successfully sued for peace. 209 BC saw Antiochus in Bactria, where another Greek, Euthydemus, had supplanted the original rebel. Antiochus again met with success. After sustaining a famous siege in his capital Bactra (Balkh), Euthydemus obtained an honourable peace by which Antiochus promised Euthydemus' son Demetrius the hand of one of his daughters.