When Alivardi khan Khan died in 1756, Sirajuddaulah became the nawab of Bengal. The Company was worried about his power and keen on a puppet ruler who would willingly give trade concessions and other privileges. So it tried, though without success, to help one of Sirajuddaulah’s rivals become the nawab. An infuriated Sirajuddaulah asked the Company to stop meddling in the political affairs of his dominion, stop fortification, and pay the revenues. After negotiations failed, the Nawab marched with 30,000 soldiers to the English factory at Kassimbazar, captured the Company officials, locked the warehouse, disarmed all Englishmen, and blockaded English ships. Then he marched to Calcutta
to establish control over the Company’s fort there. On hearing the news of the fall of Calcutta, Company officials in Madras sent forces under the command of Robert Clive, reinforced by naval fleets. Prolonged negotiations with the Nawab followed. Finally, in 1757, Robert Clive led the Company’s army against Sirajuddaulah at Plassey. One of the main reasons for the defeat of the Nawab was that the forces led by Mir Jafar, one of Sirajuddaulah’s commanders, never fought the battle. Clive had managed to secure his support by promising to make him nawab after crushing Sirajuddaulah.The Battle of Plassey became famous because it was the first major victory the company won in India.