In 1449, William was accused of treachery and imprisoned by Francesco Sforza. The reason was said to because he had formed an attachment to Sforza's wife Bianca Maria Visconti.[2] He was released a year later. Angry over his treatment by Sforza, William encouraged his brother John IV of Montferrat and relative Louis of Savoy to make war on Sforza (and Milan), and then he himself would lead the troops in battle. This attempt failed.
William later became a tutor to the couple's son Galeazzo Maria. Following his assassination, William held several positions in the Duchy of Milan.
Marriage
William married on 19 January 1465, Marie de Foix (d.1467), daughter of Gaston IV, Count of Foix;[3] and secondly on 18 July 1469, Elisabetta Sforza (d.1473),[4] daughter of Francesco I Duke of Milan and Bianca Maria Visconti;[5] and finally, on 6 January 1474, Bernarde de Brosse daughter of Jean II de Brosse.[6]
His second marriage to Elisabetta Sforza, they had:
Cereia, Daniela (2018). "Femmes a la cour de Marguerite de Broubon (1438-1483) et Claude de Brosse, comtesses de Bresse (1471-1497)". In zum Kolk, Caroline; Wilson-Chevalier, Kathleen (eds.). Femmes à la cour de France: Charges et fonctions (XVe - XIXe siècle) (in French). Presses Universitaires Septentrion. pp. 227–238.
Denieul-Cormier, Anne (1968). A Time of Glory: The Renaissance in France, 1488-1559. Doubleday.
Gregory, Winifred Terni de (1940). Bianca Maria Visconti, duchessa di Milano (in Italian). Istituto Italiano d'Arti Grafiche.
Lubkin, Gregory (1994). A Renaissance Court: Milan under Galleazzo Maria Sforza. University of California Press.
Soler, Abel (2017). L’Europa cavalleresca i la ficció literària: La cort napolitana d’Alfons el Magnanim: el context de Curial e Guelfa (in Spanish). Vol. III. Publicacions de la Universitat de Valencia.
Woodacre, Elena (2013). The Queens Regnant of Navarre: Succession, Politics, and Partnership, 1274-1512. Palgrave Macmillan.