Mitanni, controlling northern Syria and southeastern Anatolia, was a major player in the Bronze Age Near East from 1500 BC-1300 BC. They contended and negotiated with the Hittites and the Egyptian New Kingdom.
Most of the population seems to have spoken Hurrian, but there are traces of something very different in their ruling class. We have preserved diplomatic correspondence (cuneiform tablets last!) showing that the rulers of Mitanni swore by Mitra, Varuna, Indra, and Nasatya. There are other hints: names of the ruling class often make sense in Sanskrit. Kikkuli of Mitanni’s horse conditioning manual has some Indo-Aryan words (aika, tera, panza, satta). Etc. The semi-educated guess is that Indo-Aryans, as early charioteers, were hired by Mitanni as mercenaries and eventually grabbed the reins of power. After, of course, making a wrong turn at Albuquerque: North Syria is quite a ways from the known stomping grounds of the Indo-Aryans.
There’s likely an interesting story here, but we are missing almost all of it, because we have never found Washukanni, the Mitanni capital. If we did, we’d probably find lots of cuneiform tablets – as we have other capital cities of that era, such as Boğazköy.
Washukanni was probably somewhere in the Khabur triangle. Which brings me to the present, and possible near future: if we end up occupying that area, it’d be nice if we could manage a little digging on the side. We just need to start embedding archaeologists into the infantry.