Mir Jafar sought to overthrow his brother-in-law as the head of the government of Bengal and began a secret alliance with the British Empire. In the Battle of Palashi, fought on June 23, 1757, he swore by the Holy Quran to fight the British but instead informed Robert Clive of the Bengal ruler’s tactics, urging the British to advance to seize the territory. Following their victory, the British installed him as the new ruler.
Mir Jafar offered the British financial compensations to the East India Company, and promised that he would exclude France from the region. He also promised special favors to the British military and naval forces in Calcutta. Ultimately, the endless monetary concessions forced upon him by the British resulted in his financial and political ruin. In October 1760, The East India Company forced him to resign in favor of his son-in-law Mir Qasim.