Raymond died in the east in 1105, leaving his young son Alfonso-Jordan as lord of Mons Peregrinus and Tortosa (of Syria) and nominal Count of Tripoli (which had not yet been captured by the crusaders).
After Raymond's death the barons of Toulouse chose Alfonso to replace Bertrand, who, now overthrown, travelled to the east, arriving at Mons Peregrinus in 1108 to claim it for himself.
William allied himself with Prince Tancred of Galilee, at the time regent of the Principality of Antioch, while Bertrand asked King Baldwin I of Jerusalem to intervene.
With the dispute settled, the crusader armies marched on Tripoli and besieged it, with assistance from the Genoese fleet.
A short time later William died of an arrow wound sustained during the siege, and the county passed to Bertrand alone.