quality:correction
Early wars against other Hellenistic rulers

The campaigns of 219 BC and 218 BC carried the Seleucid armies almost to the confines of the Ptolemaic Kingdom, but in 217 BC Ptolemy IV defeated Antiochus at the Battle of Raphia. This defeat nullified all Antiochus's successes and compelled him to withdraw north of Lebanon. In 216 BC his army marched into western Anatolia to suppress the local rebellion led by Antiochus's own cousin Achaeus, and had by 214 BC driven him from the field into Sardis. Capturing Achaeus, Antiochus had him executed. The citadel managed to hold out until 213 BC under Achaeus's widow Laodice who surrendered later.

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 recovering the outlying provinces of the north and east. He besieged Xerxes of Armenia in 212 BC, who had refused to pay tribute, and forced his capitulation. In 209 BC Antiochus invaded Parthia, occupied the capital Hecatompylos and pushed forward into Hyrcania, winning the Battle of Mount Labus. The Parthian king Arsaces II apparently successfully sued for peace.