Antigonus III Doson
After this diplomatic failure, Aratus chose to negotiate with Antigonus III Doson, King of Macedonia, who decided to go to war against Sparta. Despite numerous attempts to break through the defensive line and reach Lechaeum in the Corinth Isthmus, Antigonus' forces failed and suffered considerable losses. At that time Argos rebelled and Cleomenes had to send 2,000 men to deal with the situation. With this lack of men, Cleomenes abandoned the Isthmus and retreated to Mantinea. At this point, Cleomenes could not avoid retreating and letting the Macedonian army advance through Arcadia.