1610 Assassination of Henri IV
Frenchmen spent the last half of the 16th century persecuting each other over the question of religion. The last stage of these conflicts was known as The War of the Three Henris because each of the factions was led by (you guessed it) someone named Henri. The last of the Valois dynasty, which pursued a variable middle course, that of the so-called “Politiques”, was Henri III. Henri, Duc de Guise, led the ultra-Catholic League, while Protestant forces were under Henri of Navarre. In 1588 Henri III had Guise murdered and in the next year a Catholic partisan took revenge by knifing the king to death. This left Navarre next in line to the throne but he only won nation-wide acceptance when he converted to Catholicism, becoming Henri IV, first of the Bourbon dynasty.
But old hatreds died hard. In 1610, François Ravaillac approached the coach of Henri IV as it was stuck in a Parisian traffic jam and plunged his dagger into the king. Though he swore, under hideous torture, that he had no accomplices and was motivated by a desire to punish someone who was no true Catholic, a recent historian has speculated that he was aided by a noblewoman, the Marquise de Verneuil, who was a spiteful discarded royal mistress, and the Duc d’Epernon who had never reconciled himself to Henri’s rule.
Ravaillac was executed in a gruesome fashion which the loathsome Michel Foucault recounted in some detail in Discipline and Punish. Suffice it here to say only that he was, after much other unpleasantness, torn apart by six horses. The standard text on the affair is Roland Mousnier, The Assassination of Henry IV.