Three minor kings followed, and later the Greek city-states of Athens and Sparta became engaged in the long Peloponnesian (pel-uh-puh-NEE-zhun) War, which lasted from 431 to 404 B. C.. At times the Persians supported Athens, at times Sparta, but in 412 b. c. they made a treaty with Sparta and assisted it in defeating Athens. In 400 b. c., Artaxerxes II (art-ag-ZURK-seez; r. 405-359 b. c.), again went to war in Greece, this time on the side of the Athenians, then revolting against the Spartan victors. After defeating the Spartans in 387 b. c., the Athenians and Persians signed an agreement respecting Persia's control over Asia Minor.
In the meantime, however, Egypt broke away from Persia, and a number of satraps almost succeeded in tearing the empire apart. The biggest threat came from Cyrus the Younger, the king's brother, who hired 10,000 Greek mercenaries (mur-sin-AIR-eez) to help him. Artaxerxes defeated him in battle but allowed many of the other rebellious satraps to remain in power. Artaxerxes III (r. 359-338 b. c.) also faced almost constant revolt, a sign that the empire was in decline. Although he managed to reclaim part of Egypt, the Egyptian rulers simply retreated upriver to Nubia or Kush and continued as before.
Artaxerxes III had usurped (yoo-SURP'D) the throne, and he killed off anyone who might try to claim it from him. But when it came to Persia's more long-term interests, he was not so careful. In 338 b. c., Athens begged Persia for help in pushing back a new force threatening Greece from the west, a king named Philip of Macedon (MAS-uh-don). Artaxerxes refused to assist the Athenians, and four years later—after he was dead and a king named Darius III was on the throne— Philip's son Alexander defeated the Persian forces in battle. After four more years, in 330 b. c., Persepolis fell to the new conqueror, better known as Alexander the Great. The Achaemenid empire was no more; a new power controlled the world.
World History
