Strategy mostly inspired by DeeDarFan. All you need to do is to persuading Ranulf, killing both Lothair and Saracens Pirates. You have to wipe off the Saracens completely to create a period that both of the Italians/Berbers allying to you and Saracens already defeated. Real matter, the yellow still remains either way. They will only resign if you kill all of their castles plus military units, no need to capture the monument. After many trials I decided to settle with this idea.