Most us were actually Buddhists at the time.
Well, us so called "cowards" formed a large part of the Islamic armies which brutally mauled you guys for a thousand years, with wounds so nasty the scars are on full display hundreds of years later. We also ended up marrying with these foreigners as well, which is why so many Pakistani/Hindustani Muslims have ancestry from Central Asia and the Middle East:
Oh and yes Muslims of the region are in fact descended from these foreign conquerors:
https://www.ncbi.nlm.nih.gov/pubmed/3163234
"The study showed that the Muslim Gujjars differ significantly from their counterpart, the Hindu Gujjars"
https://www.ncbi.nlm.nih.gov/pubmed/19809480
"Overall, our results support a model according to which the spread of Islam in India was predominantly cultural conversion associated with minor but still detectable levels of gene flow from outside, primarily from Iran and Central Asia"
https://www.ncbi.nlm.nih.gov/pubmed/20067368
"we observed a certain degree of genetic contribution from Iran to both Muslim populations"
See my previous post Abdul Cow.