Xerxes (zӗrks' ēz) I, king of Persia, was the oldest son of Darius by Atossa, his second wife, and was appointed successor by his father in preference to Artabazanes, his oldest son by his first wife. Darius died in 485 B. C. in the midst of preparations for a third expedition against Greece; and Xerxes, as soon as he had subdued the rebellious Egyptians, gave his whole attention to the completion of his father's plans for the subjugation of the Hellenic states. A bridge of boats a mile in length was built across the Hellespont; and a canal was cut through Mt. Athos, near which the fleet of Mardonius had been wrecked in 492 B. C. In the spring of 480 B. C. the vast army, said to number 2,000,000, began to march toward the Hellespont; according to Herodotus it took this force seven days and nights to march across the bridge. Grote, who discredits the immense numbers given by Herodotus, nevertheless says: "We may well believe that the numbers of Xerxes were greater than were ever assembled in ancient times or perhaps at any known epoch of history." This immense force moved on without resistance till brought to a stand by Leonidas at Thermopylæ; and, although the Greeks were defeated and slain, it was not without severe fighting and heavy loss on the part of the Persians. When Xerxes arrived at Athens, three months after crossing the Hellespont, he found the city deserted. Meantime the Persian and Greek fleets had taken their positions in the narrow strait between Salamis and the Attic coast, where the great naval battle of Salamis took place, in which the Persians were signally defeated, Xerxes himself fleeing in haste to the Hellespont. The bridge of boats having been destroyed in a storm, he crossed in a vessel, leaving Mardonius with 300,000 men to carry on operations in Greece. Next year that general was defeated by the Greeks in the famous battle of Platæa; and in 478 B. C. the Persians lost their last possession in Europe by the capture of Sestos in the Hellespont. Little more is known of the history of Xerxes, except that he was murdered by Artabanus, who aspired to the throne, and was succeeded by Artaxerxes, his son, in 465 B. C. Herodotus commended him as a man and as a monarch. See Greece, Leonidas I, Platæa, Salamis, Themistocles and Thermopylæ.
