As late as the mid-12th century, some Pashtuns appears to have not yet converted to Islam.
According to the “Ajaib al-Makhluqat” of Muhammad al-Tusi (written in 1160-1167 AD), there was a large tree with circumference of seventeen arsh (?) in a Tamarisk forest of the Pashtun country. That particular tree was known as ‘the tree of Brahman’ (درخت برهمن) and Pashtuns would prostrate before it.
Following is the original Persian text of the passage from “Ajaib al-Makhluqat” :-