True. Modern research also suggests hybrid races are genetically stronger.We Bengalis (Eastern Bengalis) have a lot of Asiatic Mongoloid blood. Especially the further South in Bangladesh you go. Lot of seafaring and trade went on in the early days, as well as Buddhist Religious expeditionary activity in between our land and the kingdoms of Myanmar, Thailand, Cambodia and China and vice versa.
The fact that we look different than the rest of Indian Hindus is also because of Muslim migrations to Eastern Bengal (in addition to Mongol blood). Detractors try to make jokes about it but I have seen this myself when I visited Gulf countries.
IMHO, the more diverse the mix, the stronger the bloodline. The more talent.
In any case - this is off topic, back to our regular programming...
What I was trying to say is that, there were actually no "Bengalis" before the period of Bengal Sultanate. The idea of Bengali identity only began during the sultanate rule with the growth of Bengali language and literature and the cultural transformation of the people under the patronization of the sultans. It's only fair to say the Sultans being our own heroes.