Xerxes I (Xerxes the Great) (zûrk´sēz), d. 465 BC, king of ancient Persia (486–465 BC). His name in Old Persian is Khshayarsha, in the Bible Ahasuerus. He was the son of Darius I and Atossa, daughter of Cyrus the Great. After bringing (484 BC.) Egypt once more under Persian rule, Xerxes prepared for an invasion of Greece (see Persian Wars) by constructing a bridge of boats across the Hellespont and cutting a canal through the isthmus of Athos. Setting out from Sardis, he marched through Thrace and Macedonia and, despite the bravery of Leonidas and his 300 Spartans, overthrew (480) the Lacedaemonians at Thermopylae. He then occupied and pillaged Athens. In the same year his fleet was destroyed at Salamis. Leaving an army under his general, Mardonius, he retired into Asia. He was slain by the captain of his bodyguard and was succeeded by his son Artaxerxes I.
See P. Green, Xerxes at Salamis (1970).