Demaratus

Demaratus (Greek: Δημάρατος) was a king of Sparta from 515 until 491 BC, 15th of the Eurypontid line, successor to his father Ariston. As king, he is known chiefly for his opposition to the other, co-ruling Spartan king, Cleomenes I. He later migrated to Achaemenid Persia where he was given asylum and land, and fought on the Persian side during the Second Persian invasion of Greece.

When Cleomenes attempted to make Isagoras tyrant in Athens, Demaratus tried unsuccessfully to frustrate his plans. In 491 BC, Aegina was one of the states which gave the symbols of submission (earth and water) to Persia. Athens at once appealed to Sparta to punish this act of medism, and Cleomenes I crossed over to the island to arrest those responsible. His first attempt was unsuccessful, due to interference from Demaratus, who did his utmost to bring Cleomenes into disfavour at home.

In retaliation, Cleomenes urged Leotychidas, a relative and personal enemy of Demaratus, to claim the throne on the ground that the latter was not really the son of Ariston, but of Agetus, his mother's first husband. Cleomenes bribed the Delphic oracle, to pronounce in favour of Leotychidas, who became king in 491 BC.

After the deposition of Demaratus, Cleomenes visited the island of Aegina for a second time, accompanied by his new colleague Leotychides, seized ten of the leading citizens and deposited them at Athens as hostages.

On his abdication, Demaratus was forced to flee. He went to the court of the Persian king Xerxes I, who gave him the cities of Pergamum, Teuthrania and Halisarna, where his descendants Eurysthenes and Procles still ruled at the beginning of the 4th century.

He accompanied Xerxes I on his invasion of Greece in 480 BC and is alleged to have warned Xerxes not to underestimate the Spartans before the Battle of Thermopylae:

Xerxes I also asks Demaratus about his knowledge of the Greeks and if they will put up a fight against the Persian army. Demaratus defends the Greeks even after being deposed and exiled from Sparta: