The Achaemenid Empire - an Empire of The Irano-Aryans

According to The Old Testament of Bible, this empire was also called The Medes Persian Empire, was a  Uni Median-Persian Empire in Western Asia, was founded in the 6th century BC by Cyrus the  Great who overthrew the Median confederation. The dynasty draws its name from King Achaemenes, king of Anshan, who ruled Persia between 705 BC and 675 BC. The empire expanded to eventually rule over significant portions of the ancient world which at around 500 BC stretched from the Indus Valley in the east, to Thrace and Macedon on the northeastern border of Greece, making it the biggest empire the world had yet seen. The Achaemenid Empire would eventually control Egypt as well. It was ruled by a series of monarchs who unified its disparate tribes and nationalities by constructing a complex network of roads.

Calling themselves Parsuha  after their original Aryan tribal name  Parsa (the Persians), settled in a land which they named Parsuha. The land is bounded on the west by the Tigris River and on the south by the Persian Gulf. This became their heartland for the duration of the Achaemenid Empire. It was from this region that eventually Cyrus the Great (Cyrus II of Persia) would advance to defeat the Median, the Lydian, and the Babylonian Empires, opening the way for subsequent conquests into Egypt and Asia Minor.

At the height of its power after the conquest of Egypt, the empire encompassed approximately      

8 million square kilometers spanning three continents: Asia, Africa and Europe. At its greatest extent, the empire included the modern territories of Iran, Iraq, Syria, Jordan, Israel, Palestine, Lebanon, and all significant population centers of ancient Egypt as far west as Libya, then Turkey, Thrace and Macedonia, much of the Black Sea coastal regions, Armenia, Georgia, Azerbaijan, much of Central Asia, Afghanistan, northern Saudi Arabia, Pakistan, and parts of Oman, and the UAE. It is noted in Western history as the antagonist foe of the Greek city states during the Greco-Persian Wars, for emancipation of slaves including the Jewish people from their Babylonian captivity, and for instituting infrastructures such as a postal system,road systems, and the usage of an official language, Aramaic, throughout its territories. The empire had a centralised, bureaucratic administration under the King and a large professional army and civil services, inspiring similar developments in later empires. The delegation of power to local governments eventually weakened the king's central authority, causing resources to be expended in attempts to subdue local rebellions. This accounts for the disunification of the region by the time Alexander the Great invaded Persia in 334 BC.

This viewpoint however is challenged by some modern scholars who argue that the Achaemenid Empire was not facing any such crisis around the time of Alexander, and that only internal succession struggles within the Achaemenid family ever came close to weakening the Empire. Alexander, an avid admirer of Cyrus the Great, would eventually cause the collapse of the empire and its disintegration around 330 BC into what later became the Ptolemaic Kingdom and Seleucid Empire, in addition to other minor territories which gained independence at that time. The Iranian Culture of the central plateau, however, continued to thrive and eventually reclaimed power by the 2nd century BC. The historical mark of the Achaemenid Empire went far beyond its territorial and military influences and included cultural, social, technological and religious influences as well. Many Athenians adopted Achaemenid customs in their daily lives in a reciprocal cultural exchange, some being employed by, or allied to the Persian kings. The impact of Cyrus the Great's Edict of Restoration is mentioned in Judeo-Christian texts and the empire was instrumental in the spread of Zoroastrianism as far east as China. Even Alexander the Great, the man who would set out to conquer this vast empire, would respect its customs, by enforcing respect for the royal Persian kings including Cyrus the Great, and even by appearing in proskynesis, a Persian royal custom, despite stern Macedonian disapproval. The Persian empire would also set the tone for the politics, heritage and history of modern Iran.