July 27 is the birthdate of Charlotte Corday, who offers a major cautionary tale. The daughter of an impoverished aristocrat, in 1793 she assassinated Jean Paul Marat, fiery proponent of the French Revolution, whom she regarded as the unholy enemy of France. Marat's death fueled the Reign of Terror, during which thousands of royalists and Girondins were executed. And yet Corday announced, prior to her decapitation, "I killed one man to save 100,000." Marat became an adulated martyr of the Revolution. Pictured: Jacques-Louis David’s “The Death of Marat” (1793).