also promised to never to cross the boundary of the Nawab's territory. European trading companies also grew more influential in Bengal. The Nawabs were also notorious for their repressive tactics, including torture for non-payment of land rent. Nawab Alivardi Khan's successor was Nawab Siraj-ud-Daulah.Nawab Siraj-ud-Daulah grew increasingly wary of the British presence in Bengal. He also feared invasions by the Durrani Empire from the north and Marathas from the west. On 20 June 1756, Nawab Siraj-ud-Daulah launched the siege of Calcutta, in which he won a decisive victory. The British were briefly expelled from Fort William, which came under the occupation of the Nawab's forces. The East India Company dispatched a naval fleet led by Robert Clive to regain control of Fort William. By January 1757, the British retook Fort William. The stalemate with the Nawab continued into June. The Nawab also began cooperating with the French East India Company, raising the ire of the British further. Britain and France were at the time pitted against each other in the Seven Years' War. On 23 June 1757, the Battle of Plassey brought an end to the independence of the Nawabs of Bengal. Nawab Siraj-ud-Daulah and his French allies were caught off guard by the defection of the Nawab's Commander-in-Chief Mir Jafar to the British side. The British, under the leadership of Robert Clive, gained enormous influence over Bengal Subah as a result of the battle. The last independent Nawab was arrested by his former officers and killed in revenge for the brutality against his courtiers. British influence and succession Mir Jafar was installed as the puppet Nawab by the British. However, Jafar entered into a secret treaty with the Dutch East India Company. This caused the British to replace Mir Jafar with his son-in-law Mir Qasim in October 1760. In one of his first acts, Mir Qasim ceded Chittagong, Burdwan and Midnapore to the East India Company. Mir Qasim also proved to be a popular ruler. But Mir Qasim's independent spirit eventually raised British suspicions. Mir Jafar was reinstalled as Nawab in 1763. Mir Qasim continued opposing the British and his father-in-law. He set up his capital in Munger and raised an independent army. Mir Qasim attacked British positions in Patna, overrunning the Company's offices and killing its Resident. Mir Qasim also attacked the British-allied Gorkha Kingdom. Mir Qasim allied with Nawab Shuja-ud-Daula of Awadh and Mughal Emperor Shah Alam