When Constantine had conquered Rome from Maxentius, he constructed a series of U-shaped funerary basilicas outside Rome. All lie beside one of the main roads leading into the city, near a catacomb where one or more saints already seem to have been venerated. With one possible exception (the basilica of the Via Ardeatina, which has not been completely excavated), a mausoleum for one or more members of the Imperial family was constructed or at least planned adjacent to the basilica. This is a novelty since Constantine’s predecessors generally built one large mausoleum close to one of the consular roads. By spreading the Imperial mausolea and placing them close to the existing centres of Christian worship, Constantine ensured that his family a...