Who, according to Herodotus, defeated and killed Cyrus the Great in 530 BC?

Tomyris was a Massagetean ruler who reigned over the Massagetae, an Iranian people from Scythian pastoral-nomadic confederation of Central Asia east of the Caspian Sea. Tomyris led her armies to defend against an attack by Cyrus the Great of the Achaemenid Empire, and, according to Herodotus, defeated and killed him in 530 BC. The names of Tomyris, and her son Spargapises, who was the head of her army, are of Iranian origins.