Learning from history: the case of the San Carlone colossus after the test of time

The investigation of the state of preservation of the Colossus of San Carlo Borromeo in Arona, Italy, San Carlone, offered the opportunity to consider the preservation of cultural heritage through a holistic approach. The scientific interest of the statue arises from the observation of the reasonable state of conservation of its metallic materials. The statue, inaugurated in 1698, consists of an outer layer of embossed copper sheets fixed to an iron armature. It is exposed to atmospheric agents with favorable conditions for galvanic corrosion between the two metals. Despite this, both the copper and iron elements show a fairly good state of preservation. The study of documents and information about selected materials, construction events, transformations, and restoration interventions are fundamental to understanding those factors— environmental, technical, physical, historical—that have led to the relatively good condition of the statue. These studies were complemented with diagnostic analyses to provide some initial conclusions regarding the continued preservation of the statue.