In the early hours of August 24, on the orders of King Charles IX and his mother Catherine de' Medici, assassins killed the Huguenot leader Admiral Gaspard de Coligny, triggering a massacre that spread through Paris and then the provinces. Estimates of the dead range from 5,000 to 30,000, and the killing deepened France's Wars of Religion for decades to come.
The massacre began as a targeted political assassination. Coligny, a Protestant leader whose influence over the young king alarmed the Catholic court, was stabbed and thrown from a window; his body was later mutilated by the mob. What followed spiraled beyond royal control. Paris, tense after a failed assassination attempt on Coligny days earlier and packed with Huguenot nobles who had come for a royal wedding meant to seal a religious truce, erupted into house-to-house killing.
Catholic militiamen, wearing white crosses on their hats to identify themselves, dragged Protestants from their beds. The Seine reportedly ran red as bodies were dumped into it. News of the slaughter spread to provincial cities—Lyon, Orléans, Rouen—where local massacres claimed thousands more lives over the following weeks. Pope Gregory XIII, on hearing the news, ordered a Te Deum sung in thanksgiving and had a commemorative medal struck.
The massacre shattered any illusion of religious coexistence in France and hardened Huguenot resistance rather than crushing it. It took the Edict of Nantes in 1598, issued by Coligny's former ally-turned-king Henry IV, to grant Protestants legal protection—protection that would itself be revoked less than a century later.