Persian Wars, wars conducted by Persia in the three expeditions against Greece, first in 490 B.C. under Darius, and defeated by the Athenians under Miltiades at Marathon; the second, 480 B.C., under Xerxes, opposed by Leonidas and his 300 Spartans at Thermopylæ and defeated by the Athenians under Themistocles at Salamis by sea; and the third, in 479 B.C., under Xerxes, by the Greeks under the Spartan Pausanius at Platæa.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Persian Gulf * Persians