While following in the familiar policy of ecclesiastical patronage, William abandoned Aleram's support of the Holy Roman Emperors.
He joined an anti-imperial alliance with Count Obert the Red, Marquis Ulric Manfred II of Turin, and Bishop Leo of Vercelli.
Even after all his allies had been pacified by imperial troops, William continued to resist Conrad II, but he fared poorly.
She prayed at the tomb of Saint Bononio, abbot of Santissimi Michele e Genuario di Lucedio.
William died in 1042, probably before 29 January, when his son Henry cites him in an act donating land to the church in Turin.