The last of the great Persian kings of the Achaemenid empire, who ruled 486-465 BC, and was the son and successor of Darius I. He is remembered chiefly for his savage destruction of Babylon after a revolt, and for his massive invasion of Greece from across the Hellespont (480 BC), with battles at Thermopylae, Salamis, and Plataea. His ultimate defeat spelled the beginning of the decline of the Achaemenid Empire.