Athens had not had a king for five hundred years. It was experimenting with a limited form of democracy under the ooverall guidance of the Council of the Aeropagus, and had ten magistrates as leaders.
Xerxes, who actually led the invasion. His father Darius I did not lead the first invasion of Greece ten years earlier, but rather sent two of his generals to do it.
The Persian War went on from 499 to 449 BCE, so there were several:
Darius I, Xerxes I, Artaxerxes I.
King Darius the Great (first)
Darius the Great.
Darius I the Great.
King Xerxes I of Persia.
Xerxes I.
King Darius I.
Darius I The Great.
Darius the Great.
Darius the Great.
Artaxerxes I.
Xerxes
Artaxerxes I.
Xerxes I was king during the Persian invasion of Greece in 480-479 BCE. Darius III was king during Alexander's conquest of Persia 150 years later and, therefore, the last Persian King of the Hellenistic Period.
Darius the Great.
Darius the Great.
The king of Persia - first Cyrus, then Cambyses, Darius, Xerxes and a string of successors.
The king of Persia and his council.