Ancient name for modern-day Iran. The country is first mentioned in annals from Assyria dating to the ninth century BC, and a few centuries later it encompassed a world empire that ruled the area from the Indus to Libya and from Babylonia to western Turkey. In 525 BC, Cambyses invaded Egypt, which began the 1st Persian Period (27th Dynasty). This would last into the 28th Dynasty when the Persians, preoccupied by trouble elsewhere, were expelled from Egypt by Amyrtaios. A 2nd Persian Period (31st Dynasty) began when Egypt was reconquered by Ataxerxes III and lasted until the arrival of Alexander the Great.