## 4 Results and Discussion  
The strongest earthquakes of the Southern Apennines, such as those in 1456 (Imax = XI MCS, Mw = 7.2), 1688 (Imax = X MCS, Mw = 6.7) and 1805 (Imax = X MCS, Mw = 6.7), reached Naples at a maximum macroseismic intensity of I = VIII on the MCS scale, with considerable damage to the architectural heritage of the historical center specifically, as in the case of Castel Nuovo, as well as to to the ecclesiastical heritage more generally. Meanwhile, the earthquakes of 8 September 1694, 23 July 1930 and 23 November 1980 caused a lower damage level of VII MCS in the urban area of Naples (Appendix A Table A1). We distinguished the levels of damage relative to historical earthquakes as belonging to three different classes of damage: minor damage (MD), serious damage (SD) and great damage/collapse (GD). In detail, the levels of damage of the 1456 and 1688 earthquakes were great and serious, concentrated in a very restricted area of the historical center of Naples (Figures 4 and 5, respectively). The 1805 earthquake resulted in a serious level of damage spread over a wider area of the historical center of the city (Figure 8), while the 1980 earthquake produced a serious level of damage that was widespread (Figure 9) in the historical center but also included minor damage diffused in the suburban areas (Figure 9). According to the different effects that the earthquakes had on the historical buildings of Naples, an original damage-density map has been elaborated upon in this paper (Figure 10), synthesizing all of the damage data on the architectural heritage that were collected ad hoc for  
Figure 9: Isoseismal map of the November 1980 Irpinia-Basilicata earthquake [56; 59; 4] (on the left). The different colors are related to the different values of MCS macroseismic intensity, and the black star is the location of the epicenter. Map of the damage caused in Naples by the earthquake on 23 November 1980 (on the right). comparison in our study. Figure 10 shows the way in which the damage repeats and overlaps in the same areas, with the greatest damages in the historic center of Naples covering an area of 17 km\({}^{2}\) and representing the most vulnerable portion of the city. Several pieces of the most famous Neapolitan architectural heritage are located in this area, including the castles/fortresses of Castel Capuano, Castel Nuovo (Maschio Angioino) and Castel Sant'Elmo, and the churches of the Cathedral, Santa Chiara, San Domenico Maggiore, San Lorenzo Maggiore, Santa Maria La Nova, San Paolo Maggiore and the Albergo dei Poveri, all of which suffered the greatest damages s a result of historical earthquakes (Figure 11). In detail, among the castles/fortresses of medieval age between the 11 th and 13 th centuries, Castel Sant'Elmo is the one that reported the greatest damage due to the earthquake of 1456, while Castel Capuano suffered the most significant damage from the earthquake of 1688. Moreover, Castel Capuano was the most affected by all of the historical earthquakes generally, as it suffered serious damages following the 1456, 1694 and 1805 earthquakes. Castel Nuovo (Maschio Angioino) was seriously damaged by the seismic events of 1688, 1694 and 1805. Considering the damage suffered by the churches, we observed that the Duomo (13 th century), Santa Chiara (14 th century), San Domenico Maggiore (13 th century), Santa Maria La Nova (13 th century) and San Paolo Maggiore (16 th century) churches suffered damage from almost all of the strong earthquakes under consideration (Figure 11). The Church of San Paolo Maggiore suffered great damage following the earthquake of 1688 and minor damage following the earthquake of 1694. The historical monumental building of the Albergo dei Poveri, among the largest buildings in Europe (18 th century), showed a different damage compared to the churches and castles/fortresses as it had severe damage only resulting from the 1805 earthquake, and partial collapses due to the 1980 seismic event.