Artaxerxes II Mnemon ("the Mindful", r. 404 – 358 BCE) was Darius II's eldest son. However, his brother, Cyrus the Younger, challenged his succession to the throne of the Achaemenid Empire.
Although Cyrus and a mixed army that included Greek mercenaries achieved a tactical victory at the Battle of Cunaxa (401 BC), Cyrus was killed in the fighting. The Greek historian Xenophon led the surviving ten thousand Greek troops, who had refused to surrender and had been allowed to keep their arms. His Anabasis recounts their part in the revolt and their five-month trek to the coast on the way home.
Having secured his throne, Artaxerxes countered growing Spartan influence in Asia Minor by subsidising their enemies, using Timocrates of Rhodes as his intermediary. As a result, the Athenians, Thebans, and Corinthians engage Sparta in what became known as the Corinthian War.
Then, faced with resurgent Athenian activity in Persia's sphere of influence, Artaxerxes withdrew his support for the allies, forcing them to negotiate. The King's Peace, a.k.a. the Treaty of Antalcidas (387 BCE), ended the Corinthian War, restored Persian control of Ionia and the Anatolian coast of Asia Minor and allowed Sparta to dominate the Greek mainland.
While Artaxerxes failed to regain control of Egypt, which had rebelled successfully at the beginning of his reign, he subsequently squashed a revolt by rebellious satraps (362 BCE). He continued to influence Greek affairs through the rest of his reign and spent a fortune on building projects, restoring Darius I's palace at Susa.