The Black Hole of Calcutta was a dungeon in Fort William, Calcutta measuring 4.30 × 5.50 ⁠metres (14 × 18 ⁠⁠feet), in which troops of Siraj ud-Daulah, the Nawab of Bengal, held British prisoners of war the night of 20 June 1756.John Zephaniah Holwell, one of the British prisoners and an employee of the East India Company, said that, after the fall of Fort William, the surviving British soldiers, Anglo-Indian soldiers, and Indian civilians were imprisoned overnight in conditions so cramped that many people died from suffocation and heat exhaustion, and that 123 of 146 prisoners of war imprisoned there died.