The event that led to the widespread use of the guillotine during the French Revolution was the escalation of revolutionary fervor and the push for justice during the Reign of Terror. The guillotine, introduced in 1792, became a symbol of revolutionary justice, representing the swift execution of those deemed enemies of the state. The increasing paranoia among revolutionaries about counter-revolutionary activities resulted in thousands of executions, including prominent figures like Louis XVI and Marie Antoinette. This period deeply shaped the course of the revolution and elicited debates about the ethics of capital punishment and justice.