Under whom did Bengal gradually break away from the Mughal control in the 18th century?

Solution

By the end of the 17th century, the Mughal Empire started facing multiple crises.  

• Emperor Aurangazeb, who was the last powerful Mughal Emperor, had exhausted the military and the financial resources of his empire by fighting a long war in Deccan.
• The efficiency of the imperial administration broke down and Mughal Emperors were not able to keep a check on the powerful mansabdars. (mansabdar referred to an individual holding mansab, meaning a position or rank.)
• Three Mughal provinces that stand out prominently are Awadh, Hyderabad, and Bengal.
• The Mansabdars of these provinces took advantage of the late 17th- century crisis.