Studies oriented to conservation and restoration of historical structures necessitate to adopt a seismic evaluation procedure as a way to better understand the structural features that characterize the construction, to investigate its safety conditions and, consequently, to estimate necessary remedial measures. Based on this background, the paper emphasizes the results of a seismic evaluation methodology carried out by the authors on an illustrative case of study, the Consoli Palace, an unfinished 14th stone masonry Praetorian Palace located in central Italy. Aimed at investigating the vulnerability of the construction to extensive damage and collapse, a multi-scale numerical analysis approach has been adopted. To this end, micro-scale analyses were performed to estimate the quality of the masonry, meso-scale (local) analyses to examine specific collapse mechanisms and, lastly, macro-scale analyses to assess the global seismic response of the building.