Most political assassinations take place in public. Julius Caesar was stabbed to death in the Roman Senate in 44 BCE , King Henry IV of France was knifed in his carriage in Paris in 1610, and Archduke Franz Ferdinand of Austria and his wife, Sophie, were shot while being driven through the streets of Sarajevo in 1914—the murder that ignited World War I. Assassinations in private are rare, but one stands out: the bathtub stabbing of Jean-Paul Marat in July 1793 by a twenty-four-year-old noblewoman from Normandy, Charlotte Corday. Although born into a minor aristocratic family, she was acting not out of devotion to royalism but because she hoped to change the course of the French Revolution by killing the journalist who had called incessantly for ever more heads to roll. Corday supported the more moderate republic advocated by the deputies known as Girondins, so called because some came from the Gironde region near Bordeaux.…