This same day is marked in one calendar as Feriae Iovi, Mercurio, Maiae. The conjunction of these deities is to some extent accidental. In the first place the Ides of every month were sacred to Jupiter; and the addition of Mercurius is probably to be explained simply by the adaptation of a Greek myth which made Hermes the son of Jupiter, suggesting the selection of the Ides as an appropriate day for the cult of the Latin representative of Hermes[472]. Mercurius, again, was associated with Maia, perhaps simply because the dedication-day of his oldest temple in Rome (_ad circum maximum_) was the Ides of the Mensis Maius[473]. The Roman Mercurius was considered especially as the god of trade, and dated, like Ceres, from the time when an extensive corn trade first began in Rome[474]. It is highly probable that the Tarquinian dynasty had encouraged Roman trade, and that the increase of population which was the result, together with the wars which followed their expulsion, had occasioned a series of severe famines. To this we trace the Roman knowledge of the Greek or Graeco-Etruscan Hermes, through a trade in corn with Sicilian Greeks or Etruscans, and the appearance of the god at Rome as Mercurius, the god of trade. His first temple was dedicated in B.C. 495, and as in other cases, the dedication was celebrated each year by those specially interested in the worship, in this case the _mercatores_, who were already, at this early period, formed into an organized guild[475]. XII KAL. IUN. (MAY 21). NP. AGON[IA][476]. (ESQ. CAER. VEN. MAFF.) VEDIOVI. (VEN.) The other days sacred to Vediovis were January 1 and the Nones of March, from which latter day we postponed the consideration of this mysterious deity, in hopes of future enlightenment. But Vediovis is wrapped still, and always will be, in at least as profound an obscurity for us as he was for Varro and Ovid. We have but his name to go upon, and two or three indistinct traces of his cult. The name seems certainly to be Vediovis, i. e. apparently ‘the opposite of,’ or ‘separated from,’ Jupiter (= Diovis); or, as Preller has it[477], comparing, like Ovid, _vegrandia farra_ (‘corn that has grown badly’), _vescus_, &c., Jupiter in a sinister sense. But this last explanation must, on the whole, be rejected. It is true that each deity has a sinister or threatening aspect as well as a smiling one; but in no other case was this separately personified, and the name, if its origin be rightly given as above (which is not indeed certain), might be explained by the well-known Roman habit of calling deities by their qualities and their business rather than by substantival names. In this case the name would be negatively deduced from that of one of the few gods who really had a name.