Up to the eighteenth century the attitude towards architectural artifacts consisted of re-use, transformation, reconstruction or adaptation of existing heritage to the changing spirit of the times. The Cathedral of Palermo is an evident example of this attitude. The symbolic value that this building has always had for the urban community has pushed the architects to intervene on several occasions on the presumably never completed body of the edifice. In the last two decades of the eighteenth century the Cathedral has undergone radical transformations that altered the original structure and determined the current configuration. As the archive of maramma, the vestry board of the Cathedral, was destroyed, the objective of this study was to reconstruct the old configuration through the use of documentary and physical traces and through the laser scanner tracking method.