Nawab Siraj-ud-Daula decided to punish the British after they had started fortifying themselves at important posts in Calcutta in violation of their treaty with him. He marched on Calcutta and seized the Company’s Fort William in June 1756. The 64 captured British residents were locked up in a small room where 23 of them were found dead the following morning. This was used by Robert Clive as an excuse to whip up anger against the Nawab. Clive’s army defeated and killed the Nawab in the Battle of Plassey in 1757.