N.K. Chauhan 
The Battle of Buxar was fought in 1764 , between the forces under the command of the British East India Company, led by Hector Munro , and the combined armies of Mir Qasim, (Nawab of Bengal till 1764); the Nawab of Awadh (Shuja-ud-Daula); and the Mughal Emperor (Shah Alam II).
"Battle of Buxar" was the most decisive battle fought by the British East India Company, it established British supremacy over India.
The war had been brought to an end by the Treaty of Allahabad in 1765.
Treaty of Allahabad (1765)
The Treaty of Allahabad was signed on 12 Aug, 1765, between the Mughal Emperor Shah Alam II and Robert Clive, of the East India Company, in the aftermath of the Battle of Buxar.Based on the terms of the agreement, Alam granted the East India Company Diwani rights, or the right to collect taxes on behalf of the Emperor from the eastern province of Bengal-Bihar-Orissa.
In return, the Company paid an annual tribute of twenty-six lakhs of rupees while securing for Shah Alam II the districts of Kada and Allahabad.
The tribute money paid to the emperor was for the maintenance of the Emperor's court in Allahabad.
Shah Alam be restored to the province of Varanasi as long as he continued to pay a certain amount of revenue to the company.
Awadh was returned to Shuja-ud-Daulah (Nawab of Awadh), but Allahabad and Kora were taken from him.
Shuja ud Daulah also had to pay fifty lakhs of rupees as war indemnity to the East India Company.
The company promised to support the Nawab against outside attacks provided he paid for services of the troops sent to his aid.
The Company appointed two deputy Diwans for the exercise of Diwani functions, i.e., Mohammad Raza Khan for Bengal and Raja Sitab Roy for Bihar.
