The Reign of Terror or simply The Terror was a period of about 11 months during the French Revolution, led by Maximilien de Robespierre. During this time, French people who did not support the revolution were executed at the guillotine.

The Reign of Terror was announced on 5 September, 1793. A Revolutionary Tribunal decided who would be killed. This happened more and more often in June and July of 1794, a period called la Grande Terreur (The Great Terror). On 17 July 1794, sixteen nuns attracted much attention by singing a religious song as they were being executed for treason. The Terror ended ten days later, when several important leaders of the Reign of Terror were executed, including Saint-Just and Robespierre. The Terror took the lives of between 18,500 to 40,000 people.