added by archaeologs An Indo-European people who moved into northwest Iran from Turkestan about 1000 BC and finally settled in the province of Pars/Parsa (modern Fars). They twice built great empires through the Middle East, under the Achaemenid family (559-330 BC) and under the Sassanians (224-651 AD). Their neighbors were the Medes. The Achaemenid empire dominated much of western Asia until it fell to Alexander the Great in the late 4th century BC. The use of the name was gradually extended by the ancient Greeks and other Western peoples to apply to the whole Iranian Plateau.