The Catacombs of Callixtus’s Crypt of the Popes bear testimony to the antiquity of Rome’s apostolic past, containing the burials of a succession of popes from the second and third centuries. Upon close examination, however, the site is not as it seems. Far from being an authentic, untouched papal burial site since the third century, I argue in Chapter 5 that the Crypt of the Popes is a (re)constructed mnemotopia for the benefit of a Catholic audience – engineered by the famed Roman “sacred archaeologist” Giovanni Battista De Rossi (1822–1894).