What is the Black Hole of Calcutta?

Niki Foster
Niki Foster

The Black Hole of Calcutta was a dungeon in colonial India in which a large number of British prisoners of war allegedly died on the night of 20 June 1756. John Holwell, one of the survivors of the incident, was responsible for the official story, but there is little objective support for his claims. Modern historians believe he may have exaggerated or even invented the story as propaganda against the Indian forces that captured Fort William, where the Black Hole was located.

A dungeon in an Indian prison came to be known as the Black Hole of Calcutta.
A dungeon in an Indian prison came to be known as the Black Hole of Calcutta.

Fort William was built by the British East India Company in 1706. In 1756, the British began to build up the fort's military defenses as a precaution against French forces in the area. Siraj Ud Daulah, the Nawab of Bengal, a hereditary local governor, ordered the British East India Company to cease their military enhancement of the fort, but he was ignored. In response, his forces laid siege to Fort William.

Nearly four days of fighting ensued, with many British casualties. The Indian forces ultimately gained the fort and took the remaining Englishmen, headed by John Holwell, as prisoners. The prisoners were initially treated well, but after some of them attacked the Nawab's guards, they were confined in a guard room and locked up overnight. This room would become the infamous Black Hole of Calcutta. Accounts differ on whether the Nawab himself or his soldiers initiated the imprisonment.

Black Hole of Calcutta was 14 by 18 feet (4.3 by 5.5 m) and had only two small barred windows. The night was hot and there was no water in the room, though the guards did provide some water when the prisoners begged for it. According to Holwell's account, some prisoners were already dead by 9:00 p.m. and the room was not opened until 6:00 the next morning. Out of 146 prisoners allegedly confined in the Black Hole of Calcutta, only 23 survived.

There are a number of problems with Holwell's account of what took place in the Black Hole of Calcutta. First of all, there is no independent support for the details he gives; even contemporary accounts varied widely on everything from the number of people confined to the conditions of the room itself. Only 43 garrison members were listed as missing from Fort William; however, Holwell listed sepoys and mixed-race people who would not have been on the list of garrison members. Some historians doubt that as many as 146 people could have remained at the fort after a four-day-long siege.

Experiments have tested whether the alleged amount of people confined in the Black Hole could have actually physically fit into a space of those dimensions. Bengali landlord Bholanath Chunder found that much less than 146 of his tenants could fit into a 15 by 18 foot (4.6 by 5.5 m) area, and Bengali villagers are on average smaller than English soldiers. Holwell's figures would have left each prisoner with only 1.8 square feet (0.55 sq. m). A 50-foot (15 m) obelisk was erected on the site of the tragedy in honor of the victims, but it was removed to the nearby St. John's cemetery in 1940, as Indian nationalists found its implications offensive.

Niki Foster
Niki Foster

In addition to her role as a wiseGEEK editor, Niki enjoys educating herself about interesting and unusual topics in order to get ideas for her own articles. She is a graduate of UCLA, where she majored in Linguistics and Anthropology.

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Discussion Comments


Even in our memory of the sides which lost the wars, like the Germans, we forget the instances in which atrocities were committed by the victors against the losers. Even though the German reich committed atrocious acts against humanity, this does not excuse the fact that the US and Russian troops were brutal toward civilian Germans in their bombings and invasions of German cities.


The atrocities committed against the Indian people were forgotten and drowned in the propaganda of the monstrous acts against English-speaking people, who could spread rumors and propaganda like wildfire. We would not have this problem if we all spoke a common language.


There are thousands of stories like these that will never be told because they involved people who are not white. The empires before the British were even more brutal toward their own people, but history tends to disregard people who kill their own people. When people conduct murders on people who are different than themselves, this is usually perceived as a greater evil. This phenomenon is likely due to out-group homogeneity bias. We think of massacres against one's own people as a form of self-punishment, when it is much worse than that.


What happened at the siege of the black hole of Calcutta, like so many events in war, is something impossible to know for sure. So much of history is written by the victors, as they say, and a lot is not recorded until long after the fact.

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