After the campaign of Ikhtiyaruddin Khalji, the Turkish-Afghans began to spread their power in Bengal. The Ilyas Shahi dynasty united the whole of Bengal and made it the most powerful empire in eastern India. The conquest of Bengal ran to Bihar, Orissa, Jharkhand, Cooch Behar, Assam, Cachar, Tripura and Arakan. Constant infighting and warfare did not keep up with Bengal's record.In 1529, Nasrat Shah made a peace treaty with the Mughal Emperor Babur and ruled Bengal as an almost independent sultan. Later Sher Khan occupied Bengal and annexed it to his empire.
The reign of the Sultans of Bengal was full of conspiracies and rebellions. The Delhiites called this region Bulgakpur or the city of rebellion. Anyone could assassinate the Sultan and seize power.In 237 years, at least 60 independent sultans ruled Bengal. There is a proverb that if you could hold the throne for at least three days, you could get the title of Sultan. Even the inhabitants of Abyssinia, who were brought to Bengal as slaves; They also killed the lords and occupied the throne for some time.