Try reading about Kafiristan, where primitive Hinduism (think Rig Veda) survived for 3500 years before being wiped out in the 1890s by a British-appointed Islamic despot.
The Kalash are very similar genetically and culturally and are also facing cultural genocide by Islamists. Truly one of the most fascinating ethnic minorities extant.
I always like to think how the region would've looked if all these remnants of peoples had thriving nations.