The Cathedral of Palermo : from survey to historic interpretation

Abstract

The Cathedral of Palermo was built by the Norman Kings, in the place where a mosque had been erected by the muslim governors of Sicily. The church has many features recalling the norman churches in northern France and in England, whilst some others are due to the contamination of norman, muslim and byzantine culture, that is peculiar of the so-called “arab-norman” architecture of medieval Sicily. In the XVIth century the Cathedral has been enriched by additions that did not affect its medieval features: a portico and a sacristy on the southern front, a sculptural decoration in the main apse. It was at the end of the XVIIIth century that the church underwent huge and extensive transformations, that deeply altered its original shape. What remains of the “enriched” Medieval church are some perspective drawings from the XVIIIth century, that cannot be used as a source for metric or proportional data, since they were commissioned when particular religious offices were celebrated, and their purpose was simply the celebration of the magnificence of the church. The Cathedral has been surveyed with topographic and laser scanning devices; some decorative elements have been surveyed with a structured light scanner. The purpose of the survey is to detect, in the actual church, all the elements survived to the transformations, and propose a virtual reconstruction of some features of monument before the end of the XVIIIth century. 3D modeling from survey data and features depicted in historic drawings have been integrated so to achieve a correct historic interpretation and a properly-dimensioned virtual reconstruction. Spherical images of the 3D reconstructive model and of the Cathedral in its actual shape have been superimposed so to highlight the differences and display hidden elements of the previous cathedral.