François de Bourbon, Prince of Conti was the third son of Louis de Bourbon, Prince of Condé, a junior line of the House of Bourbon, and his first wife Eléanor de Roucy de Roye. He was given the title of Marquis of Conti and between 1581 and 1597 was elevated to the rank of a prince. The title of Prince of Conti was honorary and did not carry any territorial jurisdiction.

Henry I, Prince of Joinville, Duke of Guise, Count of Eu, sometimes called Le Balafré ('Scarface'), was the eldest son of Francis, Duke of Guise, and Anna d'Este. His maternal grandparents were Ercole II d'Este, Duke of Ferrara, and Renée of France. Through his maternal grandfather, he was a descendant of Lucrezia Borgia and Pope Alexander VI.