The document discusses the historical roots of modern terrorism from the 18th century Enlightenment period through the early 20th century. Key events and ideologies discussed include the American and French Revolutions, the Reign of Terror, anarchist and socialist movements in Europe in the 1800s, nationalism and anti-colonial movements, and the Russian Revolution. Violent anarchist groups in the late 1800s were some of the earliest adopters of terrorism as a tactic, influencing later nationalist and revolutionary groups.