The Black Hole tragedy took place at Fort William in Calcutta in the year 1756. The Background of the Black Hole tragedy is the Nawab of Bengal gave The East India Company certain special rights as traders in Calcutta and allowed them to build a small fort (the Company named it Fort William) and maintain a small army. A few years later, the Britishers, fearing an aggression from the French, started to strengthen the fortification of Fort William. They also started to increase their army and mounted guns on the walls of the fort. Siraj-ud-daula, who was the Nawab of Bengal at that time, did not like it. He asked the Britishers to stop the fortification and scale down their military. They plainly refused the Nawab's request. Seeing his authority being flouted, that too in his own dominions, further compounded the Nawab's anger.
He launched an attack against the Britishers. After a feeble resistance of five days, the Britishers surrendered. By that time, most of them had managed to escape. Those few, who remained, were caught and taken as prisoners. These English prisoners were lodged in the prison room of the fort for a night. The prison room was 18 feet long and 14 feet wide. The number of prisoners is told to be 146 and clearly the room was too small to hold such a large number of people. It is said that out of 146, only 23 came out alive.