The premise of this question, namely that Assyria was defeated by the Persians and/or Medes is incorrect. The Assyrian Empire was only ever defeated by the Babylonian Empire. These defeats were brought about by internal strife within the Assyrian Kingdom. The Persians were able to conquer Babylon and acquire the previously conquered Assyria.
Babylonians and Scythians.
Chaldeans, Medes, Sythians
The Chaldeans and The Medes joined forces to fight The Assyrians.
The Medes and the Babylonians conquered Assyria
They were brought down by the Babylonians with help from the Medes.
During this period, the Persians were tribes to the east of the Persian Gulf, under the control of the Medes. They were farmers living off their fields and flocks with negligible resources to trade with. It was only at the end of this period that they gained control of the Medes, took over Babylonia, Assyria and the Middle East, and became a trading power as well.
There was no Persian Empire in 650 BCE. The Persian tribe was tributory to the Medes until after 550 BCE.
The Persians and the Medes, under King Cyrus the Great.
No - Darius I was not a Mede, he was Persian. And Persians and Medes were not black, they were Indo-European.
The Persian empire began when Cyrus the Great led a revolt against the Medes.
Aramaic, which was dominant in Assyria and Babylon.
In 612 B.C., the empire fell to a coalition of chaldeans and medes and was divided between those two powers.Due to the lack of records for the period of time around which the Assyrian empire fell, nobody is entirely sure why it happened. Initial examinations saw the Babylonians and Medes had defeated them, but later found works showed a civil war may have broken out before hand, contributing more to the fall than the Babylonians.