possible to suppose that Virgil here was guilty of a wilful confusion: is it possible, then, that in this cult some form of Mars is hidden behind Hercules, and that the Hercules of the _ara maxima_ is not the Genius after all, as modern scholars have persuaded themselves? But what marks out this curious cult more especially from all others is the practice of offering on the _ara maxima_ ‘decumae’ or tithes, of booty, commercial gains, sudden windfalls, and so on[817]. The custom seems to be peculiar to this cult, though it is proved by inscriptions of Hercules-cults elsewhere in Italy—e. g. at Sora near Arpinum, at Reate, Tibur, Capua and elsewhere[818]. But these inscriptions, old as some of them are, cannot prove that the practice they attest was not ultimately derived from Rome. At Rome, indeed, there is no question about it; it is abundantly proved by literary allusions, as well as by fragments of divine law[819]. Was it an urban survival from an old Italian rural custom, or was it an importation from elsewhere? In favour of the first of these explanations is the fact that the offering of _first-fruits_ was common, if not universal, in rural Italy[820]. They are not, indeed, known to have been offered specially to Hercules; but the date, Aug. 12, of the sacrifice at Rome might suggest an original offering of the first-fruits of the Roman ager, before the growth of the city had pushed agriculture to some distance away. Now first-fruits are the oldest form of tribute to a god as ‘the lord of the land,’ developing in due time into fixed tithes as temple-ritual becomes more elaborate and expensive[821]. In their primitive form they are found in all parts of the world, as Mr. Frazer has shown us in an appendix to the second volume of his _Golden Bough_[822]. It is certainly possible that in this way the August cult of the _ara maxima_ may be connected with the general character of the August festivals; that the offering of the first-fruits of harvest gave way to a regulated system of tithes[823], of which we find a survival in the offerings of the tenth part of their booty by great generals like Sulla and Crassus. As the city grew, and agriculture became less prominent than military and mercantile pursuits, the practice passed into a form adapted to these—i. e. the _decumae_ of military booty or mercantile gain[824]. But there is another possibility which must at least be suggested. The myth attached to the _ara maxima_ and the Aventine, that of Hercules and Cacus, stands alone among Italian stories, as the system of tithe-giving does among Italian practices. We may be certain that the practice did not spring from the myth; rather that an addition was made to the myth, when Hercules was described as giving the tenth of his booty, in order to explain an unusual practice. Yet myth and practice stand in the closest relation to each other, and the strange thing about each is that it is unlike its Italian kindred.