Achaemenid Empire
The Achaemenid Empire lasted from 550–330 B.C.E., it was also known as the Persian Empire, and was the state following the Median Empire, it ruled over significant portions of what is Iran. The Persian and the Median Empire together are also known as the Medo-Persian Empire, which combined territories of several earlier empires. The Persian Empire was the largest empire in ancient times; at the height of its power, the empire reached approximately 8 million km.The empire was made by Cyrus the Great, and spanned three continents Asia, Africa and Europe. At its hight, the empire included the modern day Iran, Afghanistan, Pakistan, parts of Central Asia, Asia Minor, Thrace and Macedonia, much of the Black Sea coastal regions, Iraq, northern Saudi Arabia, Jordan, Israel, Lebanon, Syria, and all significant population centers of ancient Egypt as far west as Libya. It was said that it was the enemy of the Greek city states during the Greco-Persian Wars for freeing of slaves including the Jews from Babylonianians, and for the usage of official languages throughout its territories. The empire had a centralized, bureaucratic administration under the Emperor and a large professional army, it inspired similar developments in later empires.
The Collapse
The Achaemenid Persian empire was invaded by Alexander III of Macedon, after which it collapsed and disintegrated in 330 BCE into what became the Ptolemaic Kingdom and Seleucid Empire, in addition to other minor territories which gained independence at that time. Iranian rule was re-established in the region starting from the rise of Arsacids in middle of 3rd century BCE.
http://www.ancient.eu.com/
http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Persian_Empire.html
The Collapse
The Achaemenid Persian empire was invaded by Alexander III of Macedon, after which it collapsed and disintegrated in 330 BCE into what became the Ptolemaic Kingdom and Seleucid Empire, in addition to other minor territories which gained independence at that time. Iranian rule was re-established in the region starting from the rise of Arsacids in middle of 3rd century BCE.
http://www.ancient.eu.com/
http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Persian_Empire.html