The most important step in this process was the marriage of Humbert's son Odon to Adelaida, heiress of the marquisate of Susa, whose territories extended between the Alps and the River Po (including Auriate, Turin, Ivrea and Aosta) and as far as the Mediterranean coast between Ventimiglia and Albenga, and also included control of the Alpine passes of Mont-Cenis and Saint-Bernard.