Which two brothers of Xerxes fell in the final fighting at Thermopylae?

The two brothers of Xerxes who fell in the final fighting at Thermopylae were Abrocomes and Hyperanthes. Herodotus identifies them as sons of Darius I and says they died during the struggle over Leonidas's body.

The fighting occurred after the Persians discovered the mountain path that allowed them to outflank the Greek position. Leonidas and his remaining Spartans withdrew to a small hill, where they fought with broken spears, swords, daggers, and even their hands and teeth.

Abrocomes and Hyperanthes were not sons of Xerxes in the literal sense; they were his brothers, both sons of their father Darius. Their deaths illustrate the heavy losses suffered by the Persian army despite its eventual victory.

A common mix-up is confusing these princes with Persian commanders such as Mardonius or Hydarnes. Those men played important roles in the invasion, but they were not the two royal brothers named by Herodotus as falling at Thermopylae.