What happened 281 AD

In 282 BC, Philetaerus deserted Lysimachus, offering himself and the important fortress of Pergamon, along with its treasury, to Seleucus I Nicator, who defeated and killed Lysimachus at the Battle of Corupedium in 281 BC. Seleucus was killed a few months later.

Seleucus's son and successor, Antiochus I Soter, was left with an enormous realm consisting of nearly all of the Asian portions of the Empire but faced with Antigonus II Gonatas in Macedonia and Ptolemy II Philadelphus in Egypt, he proved unable to pick up where his father had left off in conquering the European portions of Alexander's empire.

Seleucus's empire reached its greatest extent following the defeat of his erstwhile ally, Lysimachus, at Corupedion in 281 BC, after which Seleucus expanded his control to encompass western Anatolia.