The Treaty of Alinagar was signed on 9 February 1757 between Robert Clive of the British East India Company and the Nawab of Bengal, Mirza Muhammad Siraj ud-Daulah, following the decisive victory of Nawab's troops at the siege of Calcutta. Alinagar was the short-lived name given to Calcutta given by the Nawab after it was captured by him. The Nawab had seized the English fort at Calcutta, but facing the threat of Afghans in the rear and the military might of the English, he signed the treaty.