 Joan was one of six children.In 1299, Joan's mother died, probably in childbirth, and her father married his second wife, Catherine I of Courtenay, Titular Empress of Constantinople, by whom he had four more children.He would marry his third wife, Mahaut of Châtillon, in 1308, and by her he would sire a son and three daughters, among them Isabella of Valois, who became Duchess of Bourbon, and Blanche of Valois, who married Charles IV, Holy Roman Emperor.