I have often found it quite paradoxical that Bengal had such a large Muslim population, if one considers the geographical distribution of followers of the two religions in the South Asian subcontinent. If one travelled from West to East along the vast land mass known as Indo-Gangetic plain (Aryavarta) in those pre-partition days, when there were some Hindus and some Muslims in every part of the plain, one would have observed that the proportion of Muslims in the population would go on steadily reducing as one went from West to East. Thus, the North-West Frontier Province, Baluchistan and Sind were overwhelmingly Muslim ; Punjab was balanced, with a Muslim majority tapering off as one went from Attock to Ambala, west to east within the province ; and the United Provinces and Bihar were overwhelmingly Hindu. Then how is it that suddenly the pattern reversed itself in East and North Bengal, and then again fell into place in the easternmost province of British India, namely Assam?
The answer to this PROBABLY lies in that the bulk,or at least a substantial part of Bengali Muslims are converts from Buddhists, not so-called lower-caste Hindus (SCLCH), as is very often believed. This is my finding, of course arguable. Had the latter been true, so many Namahshudras, Kaibartas, Rajbongshis and others would not have remained in both West Bengal and Bangladesh. In fact huge swaths of West Bengal in the North 24-Parganas and Nadia districts (both border districts) are populated by SCLCH, mainly Namahshudras, who left everything in erstwhile East Pakistan and came away, but refused to convert to Islam. Even in present day Bangladesh there are more than a crore of Hindus (about 9% of the population), the bulk of them SCLCH. They are a majority, or nearly so, in Gopalgonj district of Bangladesh. They have a thriving religious life -- last March I visited a hugely attended and financed 'Oshtoprohor Radhakrishna Naam Yagna' near Khulna. This was in keeping with Shri Chaitanya's Bhakti cult. So it is quite difficult to accept that they constituted the bulk of Muslim converts. Some Namahshudras, of course, did convert. The rest of the minorities in that country are a few Brahmin-Kayastha-Baidya city dwellers, Saha businessmen and a handful of Buddhists and Christians. The once-powerful hold of Buddhism in present-day Bangladesh is evidenced by the extensive ruins of Mahasthangarh in Bogra district, Mainamati ruins in Comilla district and Somapura Mahavihara in Naogaon district. One more evidence is the derisive word that Bengali Hindus use for Bengali Muslims 'Neray' (the corresponding Muslim word for Hindus is 'Malaun'). Neray is a diminutive of 'Nara' which means tonsured or shaven-headed. Bengali Muslims used to shave their heads (some still do) but grow beards, a hangover from their Buddhist days. Muslims from no other part of South Asia tonsure their heads.