Peloponnesian League
Following the disastrous Spartan defeat by Thebes at the Battle of Leuktra in 371 BC, Elis and the Arcadian states seized the opportunity to throw off the yoke of Spartan hegemony; the Arcadians formed themselves into their own league to preserve their independence. The size of the Peloponnesian League was then further reduced by the Theban liberation of Messenia from Spartan control in 369 BC. The states of the north-eastern Peloponnese, including Corinth, Sicyon and Epidauros, adhered to their Spartan allegiance, but as the war continued in the 360s BC, many joined the Thebans or took a neutral position, though Elis and some of the Arcadian states realigned themselves with Sparta. In 338 BC, the Peloponnesian League was disbanded when Philip II of Macedon, father of Alexander the Great, formed the League of Corinth after defeating Thebes and Athens, incorporating all the Peloponnesian states except Sparta.