the mistress of Duke John the Fearless, by whom she had a natural son, the future bishop of Cambrai and archbishop of Trier. Several noble families of Belgium and the Netherlands descend from this prelate's eleven illegitimate children. The lines of Croÿ-Arschot-Havré and Croÿ-Rœulx stem from Antoine's two sons, Philippe I and Jean III, while his younger brother, Jean II, was the progenitor of the only extant line of the family, that of Croÿ-Solre. All three lines engaged in a complex pattern of intermarriage, so that estates and titles would stay within the family as long as possible. The line of Croÿ-Aerschot Antoine was succeeded as count of Porcéan by his eldest son, Philippe I de Croÿ, governor of Luxembourg and Ligny. Philippe I de Croÿ was raised together with Charles the Bold, who arranged Philippe's marriage to Jacqueline of Luxembourg in 1455. The bride's father was extremely against the alliance and attempted to win his daughter back by force, but the Count of Porcéan closed the borders of Luxembourg and announced that the marriage had been consummated. In 1471 Philippe defected to the king of France with 600 knights but returned to Burgundy to fight for Charles during the Battle of Nancy. During the battle he was taken prisoner. Following Charles's death, Philippe de Croÿ helped arrange the betrothal of his heiress, Marie, with Emperor Maximilian I. Toward the end of his life, he was employed by the Emperor as governor of Valenciennes, lieutenant general of Liège, and captain general of Hainaut. Philippe commissioned a remarkable church in Château-Porcien, in which he was buried upon his death in 1511. Among Philippe's sons, Antoine, Bishop of Thérouanne, predeceased his father and lies buried in Cyprus. More notable was Guillaume de Croÿ (1458–1521) (Guillermo de Chièvres, Chievres or Xebres in Spanish documents). As a tutor to Carlos I of Spain (afterwards Emperor Charles V), Guillaume became the power behind the Spanish throne during his pupil's minority, obtaining for himself the titles of Marquis of Aarschot and Duke of Soria and Archi. The Spanish aristocracy detested him as a foreigner, accusing him of pillaging the treasury and other irregularities, causing a wave of civil unrest to spread through Castile. Guillaume attended the Diet of Worms, where he was poisoned on 28 May 1521, apparently by German nobles afraid of his influence on imperial politics. Guillaume's nephew and namesake, Guillaume III de Croÿ