When did The Duel of the Mignons take place?

Les Mignons (from mignon, French for "the darlings" was a term used by polemicists in the toxic atmosphere of the French Wars of Religion and taken up by the people of Paris, to designate the favourites of Henry III of France, from his return from Poland to reign in France in 1574, to his assassination in 1589, a disastrous end to which the perception of effeminate weakness contributed. The mignons were frivolous and fashionable young men, to whom public malignity attributed heterodox sexuality, rumors that some historians have found to be a factor in the disintegration of the late Valois monarchy.

In April 1578, the rival court parties of Henry III and Henry, Duke of Guise decided to reenact the battle of the Horatii and the Curiatii. On 27 April, Jacques de Caylus, Louis de Maugiron and Jean d'Arcès (representing the party of the King) engaged in a mock battle with Charles de Balzac, Ribérac, and Georges de Schomberg (representing the party of the Guises). Maugiron and Schomberg were killed in the fighting, Ribérac died of wounds the following noon, d'Arcès was wounded in the head and convalesced in a hospital for six weeks, while Caylus sustained as many as 19 wounds and died after 33 days of agony. Only Balzac got off with a mere scratch on his arm.