The natural morphological characters, the orographic and hydrographic structures, human interventions, buildings, infrastructures, archaeological finds, are "material sources that illustrate the uses and settlement forms of the past. The literary descriptions, the artistic images, the cartographic testimonies, are verbal or iconic sources able to provide other information, dictated by the historical subject who produced them. The historiographic synthesis project should bring together the different categories of sources, in the effort of a multidisciplinary investigation".[1]