DEA DIA. – An extremely ancient Roman divinity, as is inferred from certain elements of her cult, such as the absolute prohibition on using iron tools in the ceremonies (the pruning of plants in the goddess’s sacred grove, as well as the engraving of ritual acts on marble, etc., had to be purified by a double piaculum), and the custom of venerating ancient ollae (a practice known from other authors to belong to archaic times, cf. Dionysius of Halicarnassus, II, 23); moreover, her connection with the most ancient sodality of the Fratres Arvales, whose Acta (though belonging only to the imperial age) are the sole sources transmitting news of her.
Since the deity was venerated by this sodality, which had an essentially agrarian character, it has been readily recognized that D. D. was a rustic divinity (like Ceres, Tellus, etc.), of which she would be an *indigitation*, inasmuch as her name is not a proper name in the strict sense but rather a surname. The offerings made to her—wine, dried fruit, incense, sows (the latter particularly sacred to Ceres)—also confirm her rustic character. The annual festivals of D. D. were fixed by the magister of the Arval Brothers between 7 and 12 January (through the ceremony of *inditio*), and fell in the month of May (on the 27th, 29th, and 30th). The festivities began in the city, continued in the grove and back in the city, and concluded on the third day in the city. The grove was the *locus Deae Diae* (on a hill along the Via Campana, about five miles from Rome), where the goddess’s temple stood; at the foot of the hill were the altar and the *foculus* for sacrifices, as well as other sacred buildings; nearby was a circus where, after the ceremonies in honor of the goddess, races were held.
Recently, some scholars have sought to associate D. D. (from a form *Divia*) with Diana and to see in her a lunar goddess.