be subjected to military punishment and total destruction" if the royal family was harmed, but this only increased the Revolution's will to abolish the monarchy. Some writers attitudes about French Revolution grew less favorable after the French monarchy was abolished in 1792. During the Reign of Terror, which began in July 1793 and lasted thirteen months, Paris was governed by the Committee of Public Safety who oversaw a regime of mass executions and public purges. Prior to the French Revolution, ancient philosophers wrote about tyrannicide, as tyranny was seen as the greatest political threat to Greco-Roman civilization. Medieval philosophers were similarly occupied with the concept of tyranny, though the analysis of some theologians like Thomas Aquinas drew a distinction between usurpers, who could be killed by anyone, and legitimate rulers who abused their power—the latter, in Aquinas' view, could only be punished by a public authority. John of Salisbury was the first medieval Christian scholar to defend tyrannicide. Most scholars today trace the origins of the modern tactic of terrorism to the Jewish Sicarii Zealots who attacked Romans and Jews in 1st-century Palestine. They follow its development from the Persian Order of Assassins through to 19th-century anarchists. The "Reign of Terror" is usually regarded as an issue of etymology. The term terrorism has generally been used to describe violence by non-state actors rather than government violence since the 19th-century Anarchist Movement. In December 1795, Edmund Burke used the word "Terrorists" in a description of the new French government called 'Directory': At length, after a terrible struggle, the [Directory] Troops prevailed over the Citizens ... To secure them further, they have a strong corps of irregulars, ready armed. Thousands of those Hell-hounds called Terrorists, whom they had shut up in Prison on their last Revolution, as the Satellites of Tyranny, are let loose on the people.(emphasis added) The terms "terrorism" and "terrorist" gained renewed currency in the 1970s as a result of the Israeli–Palestinian conflict, the Northern Ireland conflict, the Basque conflict, and the operations of groups such as the Red Army Faction. Leila Khaled was described as a terrorist in a 1970 issue of Life magazine. A number of books on terrorism were published in the 1970s. The topic came further to the fore after the 1983 Beirut barracks bombings and again after the 2001 September 11 attacks and the 2002 Bali bombings. Modern definitions In 2006 it was estimated