On 18 August 1572, Paris hosted the lavish wedding of Marguerite de Valois and Henri de Navarre, which was designed to seal the reconciliation of France’s Catholics and Protestants. Only six days later, the execution of the Protestant leaders on the orders of the king’s council unleashed a vast massacre by Catholics of thousands of Protestants in Paris and elsewhere. Why was the celebration of concord followed so quickly by such unrestrained carnage? Arlette Jouanna’s new reading of the most notorious massacre in early modern European history rejects most of the established accounts, especially those privileging conspiracy, in favour of an explanation based on ideas of reason of state. The Massacre stimulated reflection on royal power, the limits of authority and obedience, and the danger of religious division for France’s political traditions. Based on extensive research and a careful examination of existing interpretations, this book is the most authoritative analysis of a shattering event.