The Achaemenid Empire (//; Old Persian: 𐎧𐏁𐏂, romanized: Xšāça, lit. 'The Empire'), also called the First Persian Empire, was an ancient Iranian empire that was based in Western Asia and founded by Cyrus the Great in 550 BC. It reached its greatest extent under Xerxes I, who conquered most of northern and central ancient Greece, including the city of Athens, in 480 BC. At its greatest territorial extent, the Achaemenid Empire stretched from the Balkans and Eastern Europe in the west to the Indus Valley in the east. The empire was larger than any previous empire in history, spanning a total of 5.5 million square kilometers (2.1 million square miles).
|550 BC–330 BC|
King of Kings
• 559–529 BC
|Cyrus the Great|
• 336–330 BC
|Historical era||Classical antiquity|
|500 BC||5,500,000 km2 (2,100,000 sq mi)|
|17 million to 35 million|
The empire had its beginnings in the 7th century BC, when the Persians settled in the southwestern portion of the Iranian Plateau, in the region of Persis. From this region, Cyrus rose and defeated the Median Empire—of which he had previously been king—as well as Lydia and the Neo-Babylonian Empire, following which he formally established the Achaemenid Empire.
The Achaemenid Empire is known for imposing a successful model of centralized, bureaucratic administration via the use of satraps; its multicultural policy; building infrastructure, such as road systems and a postal system; the use of an official language across its territories; and the development of civil services, including its possession of a large, professional army. The empire's successes inspired the usage of similar systems in later empires.
Alexander the Great, an ardent admirer of Cyrus the Great, conquered most of the Achaemenid Empire by 330 BC. Upon Alexander's death, most of the former territory of the empire fell to the rule of the Ptolemaic Kingdom and the Seleucid Empire. The Iranian elites of the central plateau reclaimed power by the 2nd century BC under the Parthian Empire.