Xerxes I or Xerxes the Great (c.519-465 BC) succeeded his father Darius I to the throne of Persia in 486 BC, in spite of the fact that he had an older brother Artabazanes. He continued his father's war campaign against Greece. Their grievance was the Greek's aid to the Ionians revolt from Persia. He amassed a huge army of around 200,000 men and in 480 BC invaded Greece. A famous battle occured at Thermopylae where a few thousand Greeks held off Xerxes' forces for ten days before losing. Xerxes next conquered Attica and Athens.

Later that year, his naval fleet was defeated by the Athenian Themistocles, and his army suffered huge losses to disease. Xerxes returned to Persia, Susa to be precise, while his brother-in-law Mardonius was left in command.

Before this campaign, however, the first thing he had to do as king was to subdue Egypt. There a usurper had been in power for a couple years, so he travelled to Egypt and "chastized" them. (ahem) He then had to deal with revolt in Babylon. Finally, Xerxes allowed Egypt and Babylon some more autonomy than his father had, abandoning the title of king of Babylonia and Egypt for the title king of the Persians and the Medes.

Xerxes was murdered in 465 BC by the captain of the palace guard (glorified butler!) and was succeeded by his son Artaxerxes I.

According to Encarta, Xerxes is identified as the Ahasuerus of the Book of Esther. I also suspect that Xerces is an alternate or corrupted spelling of Xerxes. A bas-relief of Xerxes exists on the southern portico of a courtyard in the treasury of Persepolis.