The gods and goddesses of the city of Rome provide us with a well-defined body of supernatural beings: they were familiar to all Italians in ancient times as images and identifiable as such, by dress and by the symbols that accompanied them; they were recognisable when they appeared in dreams in their familiar guise; they sent communications in various forms to their human worshippers, sometimes spontaneously, sometimes in response to requests; they could be, and were, relied on for help in daily life; they could be seen as members of the Roman community, in some respects resembling their human worshippers, though far more powerful. On the other hand, their number was never fixed and the Romans only stopped acquiring new gods and goddesses as their traditional ways of worship began to be undermined in the later periods of the Empire. At the same time, it was by no means impossible for older gods and goddesses to be neglected or forgotten; it was apparently fear of this erosion (perhaps misplaced fear) that led the antiquarian writer Varro to write a massive record of them in a lost work, known to us mostly from Christian writers such as Arnobius of Sicca and Augustine of Hippo, who quarried the details of Varro’s work in search of materials to discredit the traditional religious practices of those the Christians had by then begun to call ‘pagans’.