Battle of Mantinea
Although initially successful in resisting Spartan influence in Arcadia, the league was soon divided in the power struggles that engulfed Greece in the 4th century BC. Thebes, which had been instrumental in the founding of the league, soon came into conflict with Mantinea. At the Battle of Mantinea (362 BC), the cities of the league fought against each other, Mantinea fighting alongside Sparta and Athens, while Tegea and others sided with Thebes.