The term terrorist is believed to have originated during the Reign of Terror (September 5, 1793July 28, 1794) in France. It was a period of eleven months during the French Revolution when the ruling Jacobins employed violence, including mass executions by guillotine, in order to intimidate the regime's enemies and compel obedience to the state. The Jacobins, most famously Robespierre, sometimes referred to themselves as "terrorists". Some modern scholars, however, do not consider the Reign of Terror a form of terrorism, in part because it was carried out by the French state. French historian distinguishes between the revolutionary terror of the French Revolution and the terrorists of the September 11 attacks: