Dius Fidius, as the adjectival character of his name shows, was a genuine old Italian religious conception, but one that in historical times was buried almost out of sight. Among gods and heroes there has been a struggle for existence, as among animals and plants; with some peoples a struggle between indigenous and exotic deities, in which the latter usually win the day, and displace or modify the native species[547]. What laws, if any, govern this struggle for existence it is not possible to discern clearly; the result is doubtless the survival of the fittest, if by the fittest we understand those which flourish best under the existing conditions of society and thought; but it would hardly seem to be the survival of those which are most beneficial to the worshipping race. Among the Romans the fashionable exotic deities of the later Republic and Empire had no such ethical influence on the character of the people as those older ones of the type of Dius Fidius, who in historical times was known to the ordinary Roman only through the medium of an old-fashioned oath. Ovid knows very little about Dius Fidius[548]: Quaerebam Nonas Sanco Fidione referrem, An tibi, Semo pater: cum mihi Sancus ait ‘Cuicunque ex illis dederis, ego munus habebo; Nomina trina fero, sic voluere Cures.’ He finds three names for the deity, but two would have sufficed; the only individual Semo known to us is Sancus himself. The Semones, so far as we can guess, were spirits of the ‘pandaemonic’ age, nameless like the Lares with whom they are associated in the hymn of the Fratres Arvales[549]; but one only, Semo Sancus, seems to have taken a name and survived into a later age, and this one was identified with Dius Fidius. Aelius Stilo, the Varro of the seventh century A. U. C., seems to have started this identification[550]. Varro does not comment on it; but Verrius accepted it: he writes of an ‘aedes Sancus, qui deus Dius Fidius vocatur’[551]. The evidence of inscriptions is explicit for a later period; an altar, for example, found near the supposed site of his temple on the Quirinal, bears the inscription ‘Sanco Sancto Semon[i] deo fidio sacrum’[552]. And there is nothing in the words Sancus and Fidius to forbid the identification, for both point to the same class of ideas—that of the bond which religious feeling places on men in their duties to, and contracts with, each other. They are in fact two different names for the same religious conception. It is interesting to find them both occurring in the great processional inscription of Iguvium in Umbria: Fisus or Fisovius Sancius, who is there invoked next after Jupiter, seems to unite the two deities in a single name[553]. This conjunction would seem to save us from the necessity of discussing the question whether Sancus, as has often been insisted on by scholars both ancient and modern[554], was really the Sabine form of Dius Fidius;