DEA DIA. The worship of the Roman goddess Dea Dia was in the hands of a priesthood of twelve, the fratres arvales (Arval brethren), and she possessed a shrine in a grove outside Rome at the fifth (or sixth, depending on the period) milestone on the Via Campana, in the modern suburb of La Magliana. The deity, her cult, and her priesthood supposedly date back to very early in Roman history, but they underwent a major renovation by Augustus (r. 27 BCE–14 CE). From the previous period, we only know of the existence of the arvales and of a public sacrifice, mentioned by Varro (De lingua latina 5, 74). The site itself bears testimony of cultic occupation since at least the third century BCE. But it is impossible to be sure whether these items belonged to Dea Dia or to Fors Fortuna, who possessed a temple on the same...