Mir Jafar was now the Nawab of Bengal, the company was not even at the time was interested in the administration or conquest and kept expansion of trade as their first priority.
Over a period of time, even Mir Jafar got tired of the company demands and protested, in return company deposed and installed Mir Qasim.
Mir Qasim when protested taking the help of Nawab of Awadh Shuja-ud-Doula, Mughal emperor Shah Alam II and Raja Balwant Singh of Kashi. It turned into a war
The war is called Battle of Buxar, in 1764at a small place in Bihar on the riverbank of Ganga, and Mir Qasim was defeated in the battle and Mir Jafar was made Nawab of Bengal for the second time.
Battle of Buxar was a decisive victory of East India Company in India.
After the war, Mir Jafar was made to pay huge expenses to the company for the maintenance of their army and meet their trade expanses, but still the British were not satisfied.
After the death of Mir Jafar, Company decided to take the control itself and in 1765, Company was appointed as Diwan of provincesof Bengal by the Mughal emperors.
The company now have got the enormous power to exploit the resources and people of Bengal and those company officials who earned enormous wealth from India were called nabobs(an anglicized version of Nawab).