This is one of the more obscure kingdoms of the 2nd millennium BC. One of the ancient non-Semitic and non-Indo-European peoples of the Middle East, the Hurrians briefly come into their own. Just where they came from is obscure. It was previously thought that some time after 2000 they moved out of the mountains and occupied the great bend of the Euphrates River and the upper Tigris Valley, but new discoveries hint that they occupied these areas originally.
Previously, it was thought that, around 1600, an Iranian people, the Mitanni, had established themselves among the Hurrians as a warrior aristocracy, founding the Kingdom known by that name. If there had been a foreign warrior aristocracy, it looks like it was assimilated rapidly and left few traces by the time of Shattiwaza.
The Indo-Aryan influence is unmistakeable. The proximity of durable Into-Aryan speakers in Iran is obvious. The only question is the extent of the influence, or of the physical presence of Iranians among the Hurrians.
Characteristic of the obscurity of the history of this kingdom, the capital, Washukkanni, has never been positively located, leaving us without direct documentary evidence of Mitannian history from archives or inscriptions. The dating is thus, even for the period, especially problematic. And, as the Hurrians themselves were subsequently assimilated into later linguistic communities, ultimately that of Aramaic speakers, any evidence of Iranians who might be been assimilated among them is lost even more.
The short history of the kingdom was an important period in the history of the Middle East. The first kings had to contend with Egypt at the height of its military power in the XVIII Dynasty. Both Thutmose I and Thutmose III reached the Euphrates; but the Mitanni eventually fought the Egyptians to at least a draw, and cordial relations ensued, including marriages between the courts. About a century as a Great Power follows.
The Hittites, emerging from a period of confusion, then upset the status quo with a devastating defeat of Tushratta, setting off a precipitous decline in the kingdom. Rival claimants for the throne soon enabled Assyria, a Mitanni vassal for more than a century, to regain her independence, the Hittites returned to reduce a rump Mitanni state to Hittite vassalage, and finally the Assyrians swept the kingdom into history, soon with nothing left to mark the existence of either the Mitanni or the Hurrians.