When Leonidas died, in 236, Cleomenes became the only king, but he was so young that Aratus and the Achaians thought it a good time for extending the power of their league at the expense of Sparta; so, though no war was going on, Aratus sent a troop by night to seize Tegea and Orchomenus, cities in alliance with Sparta.  But his designs were found out in time for Cleomenes to strengthen the garrisons in both places, and march himself to a place called the Athenæum, which guarded one of the passes into Laconia.