Page "Geoffrey II, Count of Anjou" Paragraph 4

Allied once again with King Henry, Count Geoffrey assaulted Normandy and seized the towns of Domfront and Alençon, evidently with the help of treachery within.

Duke William laid siege to Domfront, which resisted his efforts to retake it throughout the winter of 1052.

And it was at this point that Talou withdrew from the siege and started his rebellion.

Duke William's subsequently rapid retaking of first Alençon and then Domfront drove Count Geoffrey back across the Norman border into Maine.