Their eldest son Count Oddone I (Otto) died about 991; his wife's name was Marie but her background is unknown. Their son was known as William III of Montferrat, though it is unclear who "William I" was. He died about 1031, and his wife's name is unknown. He was the father of two sons: Enrico I, who died childless, and Oddone II, marquis of Montferrat (1044-1084) who married Constanza of Savoy, daughter of Count Amadeo II (see Savoy). Their son William IV (died 1100) married Aude, daughter of Tibaldo d'Aglie (about whom nothing else is known). They were the parents of Rainier II (c1075-1135), who married Gisela of Burgundy (daughter of Guillaume I 'the Great' and Stephanie de Longwy). They had six children: William V 'the Old' (c1110-1191, see below); Adelicia, married William ****o, a grandson of William the Conqueror); Giovanna, married Alexius Comnenus; Matilde, married Alberto di Massa, Marchese di Gavi e Parodi; Beatrice, married Guy V, dauphin of Viennois; and Isabelle, married Guido di Biandrate.
William V 'the Old' married Judith von Babenberg, daughter of Leopold III, Margrave of Austria and his wife Agnes, daughter of the emperor Henry IV (see Hohenstaufen). They had ten children, at least two of whom we are descended from: (1) the second son, Conrad of Montferrat (died 1192), Prince of Tyre, who married as his second wife Isabelle of Anjou, Queen of Jerusalem; they were the parents of Maria, Queen of Jerusalem 1206-1212, who married Jean de Brienne); and (2) Alasia, c1160-1202, who married Manfredo II of Saluzzo. The Montferrat line continued with their brother Bonifacio I, whose titles eventually descended to Empress Irene of Constantinople.