[Sherman Logan]

Mitanni is another name for Medes; the northwest part of Medes retained this name as Matiane (Herodotus).

This is one theory, it is by no means proven fact.

The Mitanni Empire fell around 1300. The Medes emerged as a great power around 700.

Trying to connect two peoples 600+ years apart as "the same people" is pretty tough.

Mitanni was Hurrian in language, with initially an Aryan ruling class, but which apparently switched to Hurrian language before long.

The Medes were very much Aryan.

[SunkenCiv]

The fact is, Mitanni didn’t even arise until after 1300 BC — these are two names for the same people.