The most probable supposition is that this day being, as Ovid implies, the dies natalis of one of the temples of Venus[293], the Vinalia also came to be considered as sacred to the goddess. The date of the foundation was 181 B.C., exactly at a time when many new worships, and especially Greek ones, were being introduced into Rome[294]. That of the Sicilian Aphrodite, under the name of Venus, seems to have become at once popular with its _Graecus ritus_ and _lascivia maior_[295]; and the older connexion of the festival with Jupiter tended henceforward to disappear. It must be noted, however, that the day of the Vinalia Rustica in August was also the dies natalis of one if not two other temples of Venus[296], and one of these was as old as the year B.C. 293. Thus we can hardly avoid the conclusion that there was, even at an early date, some connexion in the popular mind between the goddess and wine. The explanation is perhaps to be found in the fact that Venus was specially a deity of gardens, and therefore no doubt of vineyards[297]. An interesting inscription from Pompeii confirms this, and attests the connexion of Venus with wine and gardens, as it is written on a wine-jar[298]:
PRESTA MI SINCERU[M] ITA TE AMET QUE CUSTODIT ORTU[M] VENUS.
The Vinalia, then, both in April and August, was really and originally sacred to Jupiter. The legendary explanation is given by Ovid in 11. 877-900. Whatever the true explanation may have been, the fact can be illustrated from the ritual employed; for it was the Flamen Dialis[299] who ‘vindemiam auspicatus est,’ i. e. after sacrificing plucked the first grapes. Whether this auspicatio took place on either of the Vinalia has indeed been doubted, for even August 19 would hardly seem to suit the ceremony Varro describes[300]; but the fact that it was performed by the priest of Jupiter is sufficient for our purpose.
Of this day, April 23, we may guess that it was the one on which the wine-skins were first opened, and libations from them made to Jupiter. These are probably the libations about which Plutarch[301] asks ‘Why do they pour much wine from the temple of Venus on the Veneralia’ (i. e. Vinalia)? The same libations are attested by Verrius: ‘Vinalia diem festum habebant quo die vinum novum Iovi libabant’[302]. After the libation the wine was tasted, as we learn from Pliny[303]; and it seems probable that it was brought from the country into Rome for this purpose only a few days before. Varro has preserved an interesting notice which he saw posted in vineyards at Tusculum: ‘In Tusculanis hortis (MSS. sortis) est scriptum: ‘Vinum novum ne vehatur in urbem ante quam vinalia kalentur’[304]; i. e. wine-growers were warned that the new wine was not to be brought into the city until the Vinalia had been proclaimed on the Nones. It must, however, be added that this notice may have had reference to the Vinalia in August; for Verrius, if he is rightly reported by Paulus[305], gives August 19 as the day on which the wine might be brought into Rome. Paulus may be wrong, and have confused the two Vinalia[306]; but in that case we remain in the dark as to what was done at the Vinalia Rustica, unless indeed we explain it as a rite intended to secure the vintage that was to follow against malignant influences. This would seem to be indicated by Pliny (_H. N._ 18. 284), where he classes this August festival with the Robigalia and Floralia[307], and further on quotes Varro to prove that its object was to appease the storms (i. e. to be expected in September).