The following year he began his association with the king's brother Anjou, future Henri III, fighting under his command during the siege of La Rochelle.

Neither side delivered a fatal blow and Henri frustratedly insisted the two men make a show of reconciliation.

The king mourned his loss to an extent that was viewed improper by contemporaries and commissioned an elaborate tomb for his dead favourites.

[3][4] Caylus entered political life in 1572, when he was dispatched to court by his father, to inform the king of Antoine's failure to reduce the Protestant towns of Montauban and Millau.

[9] At the age of 18, Caylus was among the ambitious young nobles who flocked to join the siege of La Rochelle, the city having gone into rebellion after the Massacre of Saint Bartholomew.

[3] Upon hearing of his brother's death, and the vacancy of the French throne, Anjou, now styling himself Henri III determined to race back, abandoning his kingship in the Commonwealth.

Sneaking out of Kraków he rendezvoused with René de Villequier, Caylus and Pibrac near Oświęcim who were leading a separate body of French gentleman, guides and translators, from where they continued their flight back to France.

[10][11] Upon re-entering France, Henri stalked the streets of Lyon with his close friends, among them François d'O, Du Guast and Caylus.

[12] While tarrying in Lyon Henri approved the elevation of Caylus' fief to a county, confirming a promise he had made to his friend the previous year.

[5] In November 1575 Caylus became gentleman of the chamber to the French king, taking up a post he had previously held in the Commonwealth.

[18] During the sixth civil war in 1577, he fought with the crown, and was captured by a Protestant army near Brouage, alongside La Guiche, another favourite of Henri's.

[23] L'Estoile who compiled parisian remembrances of the event, found that almost every pamphlet praised Entraguet for his victory, while denouncing Henri's favourites as 'sodomites'.

[5] After his death Caylus was laid in state with his face left open, an honour usually reserved for nobles of the highest rank.

He fashioned large sarcophagi out of black marble with a figure kneeling as they read a book of prayer on the top of the sarcophagus.