CASTEL SANT'ANGELO AND THE BRONZE OF THE PANTHEON At the end of the fourteenth century Castel Sant'Angelo became an impregnable fortress, when Pope Boniface IX had a deep moat dug around the Mausoleum. As Biondo Flavio recounts in the mid-fifteenth century, the pope transformed it into «the mo... To read the full article you must log in or register. Login or register