Most ethnicities has one dominant religion. Vast majority of them follows it/borne into it. For Turks, Arabs and Iranians it is Islam. Interestingly for Bengalis, roughly one fourth are Hindus and 3/4 are Muslims. Though we have been leaving side by side for thousand years. But the most crazy part is how we changed our religion all together. I mean Bengal, more specifically East Bengal was neither hindu nor Muslim majority. It was Buddhist majority. This region was the bastion of Buddhism. Pala empire period considered the golden age of Buddhism. They truly build a great civilization. And then your ancestors came form central Asia on horses and wiped them out. But they also converted us to Islam. So I have mixed feelings.
Conversion to Islam was gradual and happened slowly.
The factors have all varied but despite the Seljuks and the Golden Horde all becoming Muslim they still had soldiers who believed in Tengri.
Lots of our tales and legends have still been around albeit they gave it a Islamic flavour.
Wolves and Wise old Men still continued well into the Islamic Era.
When the Mongols conquered Central Asia became Muslim overtime they actually Islamised the region even more with the Chagatai Khanate.
Yuan Dynasty was only one not to become Muslim out of the Mongol divisions.
Genghis Khan was a Tengrist but his successors overtime left the Nomadic way of life and took up different religions.
Genghis Khan himself predicted one day his descendants will be living in palaces.
Genghis Khan might be a reviled figure worldwide but lots of Turks and Mongols claimed to be his successor like Timur, Babur even the Ottomans.
Despite the damage lots of Muslim Turco Mongols held him in high regard.
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