 Pope Urban IV and Pope Martin IV both lived in the town and probably oversaw construction of the initial stages of this building.Pope Boniface VIII extended the building, but it was left unfinished following the papal move to Avignon in 1309.It remained a papal residence until 1550, when it was passed to the ownership of the cathedral, who after using it as a residence for some time redesigned it in 1896 as a museum, which it remains today.