For most of the first years of his reign, Agesilaus had been engaged in a war against Persia in the Aegean Sea and in Asia Minor. In 394 BC, the Spartan authorities ordered Agesilaus to return to mainland Greece. While Agesilaus had a large part of the Spartan Army in Asia Minor, the Spartan forces protecting the homeland had been attacked by a coalition of forces led by Corinth. At the Battle of Haliartus the Spartans had been defeated by the Theban forces. Worse yet, Lysander, Sparta's chief military leader, had been killed during the battle. This was the start of what became known as the "Corinthian War" (395–387 BC). Upon hearing of the Spartan loss at Haliartus and of the death of Lysander, Agesilaus headed out of Asia Minor, back across the Hellespont, across Thrace and back towards Greece. At the Battle of Coronea, Agesilaus and his Spartan Army defeated a Theban force. During the war, Corinth drew support from a coalition of traditional Spartan enemies—Argos, Athens and Thebes. However, when the war descended into guerilla tactics, Sparta decided that it could not fight on two fronts and so chose to ally with Persia. The long Corinthian War finally ended with the Peace of Antalcidas or the King's Peace, in which the "Great King" of Persia, Artaxerxes II, pronounced a "treaty" of peace between the various city-states of Greece which broke up all "leagues" of city-states on Greek mainland and in the islands of the Aegean Sea. Although this was looked upon as "independence" for some city-states, the effect of the unilateral "treaty" was highly favourable to the interests of the Persian Empire.