From the time of the Assassins (late 13th century) to the1700s, terror and barbarism were widely used in warfare and conflict, but key ingredients for terrorism were lacking. Until the rise of the modern nation state after the Treaty of Westphalia in 1648, the sort of central authority and cohesive society that terrorism attempts to influence barely existed. Communications were inadequate and controlled, and the causes that might inspire terrorism (religious schism, insurrection, ethnic strife) typically led to open warfare. By the time kingdoms and principalities became nations, they had sufficient means to enforce their authority and suppress activities such as terrorism.

The French Revolution provided the first uses of the words "Terrorist" and "Terrorism". Use of the word "terrorism" began in 1795 in reference to the Reign of Terror initiated by the Revolutionary government. The agents of the Committee of Public Safety and the National Convention that enforced the policies of "The Terror" were referred to as 'Terrorists". The French Revolution provided an example to future states in oppressing their populations. It also inspired a reaction by royalists and other opponents of the Revolution who employed terrorist tactics such as assassination and intimidation in resistance to the Revolutionary agents. The Parisian mobs played a critical role at key points before, during, and after the Revolution. Such extra-legal activities as killing prominent officials and aristocrats in gruesome spectacles started long before the guillotine was first used.