 There are striking similarities between Avestan and Sanskrit, which may support the notion that the split was contemporary with the Indo-Aryans living in Afghanistan at a very early stage.Also, the Avesta itself divides into Old and New sections and neither mention the Medes who are known to have ruled Afghanistan starting around 700 BC.This suggests an early time-frame for the Avesta that has yet to be exactly determined as most academics believe it was written over the course of centuries if not millennia.