Achaemenid Persian Empire (550–330 BC) was the largest empire of the ancient world[2] and the most widespread entity of it was under Darius the Great and Xerxes (or Xerkes) — famous in antiquity as the foe of the classical Greek states (See Greco-Persian Wars) — a united Persian kingdom that originated in the region now known as Pars province (Fars province) of Iran.
It was formed under Cyrus the Great, who took over the empire of the Medes, and conquered much of the Middle East, including the territories of the Babylonians, Assyrians, the Phoenicians, and the Lydians. Cambyses, Son of Cyrus the Great, continued his conquests by conquering Egypt. The Achaemenid Persian Empire was ended during the Wars of Alexander the Great, but Persian Empire arose again under the Parthian and Sassanid Empires of Iran, followed by Iranian post-islimic Empires like Safavids, up to the modern day Iran.
Most of the successive states in Greater Iran prior to March 1935 are collectively called the Persian Empire by Western historians.
Virtually all the successor empires of Persia were major regional and some major international powers in their day.
The Medes are credited with the foundation of the first Iranian empire, the largest of its day until Cyrus the Great established a unified Iranian empire of the Medes and Persians, often referred to as the Achaemenid Persian Empire, by defeating his grandfather and overlord, Astyages the shah of Media. The Median capital was Ecbatana, the modern day Iranian city of Hamedan. Ectbatana was preserved as one of the capital cities of the Achaemenid Empire, which succeeded the