 Between 2000–1200 BC, a branch of Indo-European-speaking tribes known as the Aryans began migrating into the region.This is part of a dispute in regards to the Aryan invasion theory.They appear to have split into Iranic peoples, Nuristani, and Indo-Aryan groups at an early stage, possibly between 1500 and 1000 BC in what is today Afghanistan or much earlier as eastern remnants of the Indo-Aryans drifted much further west as with the Mitanni.