Murshid Quli Khan who was the founder of the Nasiri dynasty was the first Nawab of Bengal. After the death of Mughal emperor Aurangzeb, he became the first independent ruler of Bengal. His early life is rooted in controversy and nothing particular can be said about his family and parenthood. Murshid Quli Khan entered the services of Aurangzeb and progressed gradually before becoming the Nawab of Bengal in 1717. He died in 1727 and was succeeded by his son-in-law though the late Nawab desired his grandson to be his heir.
The second dynasty was the Afshar dynasty which ruled from 1727 to 1757 was established by Alivardi Khan. The last rulers of this dynasty Siraj ud Daula was killed in the Battle of Plassey in the year 1757. Siraj Ud Daula was the last independent Nawab of Bengal. In the battle of Plassey he suffered loss in the hands of the British forces. Since then the Nawabs became dummy rulers under the supremacy of the British. The Nawab who ascended the throne of Siraj-ud-daula was Mir Jafar. When the then Mughal emperor Shah Alam II granted the Diwani rights of Bengal, Bihar and Orissa to the British East India Company in 1765, the Nawabs were deprived of any real power or authority.
The last and the final dynasty to rule Bengal is the Najafi dynasty which came into power in the year 1757 and ruled until 1880. During this time the Nawabs hardly exercised any power of their own. In the year 1793 the governorship was taken away from the Nawabs and they were reduced to just being mere pensioners of the British East India Company. Mansur Ali Khan, the last Nawab of the Najafi dynasty was forced to give up his title. He was succeeded by his son Nawab Sayyid Hassan Ali who was conferred the lesser title of Nawab of Murshidabad by the British. His successors continued to rule with the same title until 1969.
The reign of the Bengal Nawabs came to an abrupt halt due to weak successors and the invasion of the British. Although the office of the nawabs existed but they were mere puppets in the hands of the British.