Until the issue of Altheim's book Roemische Religionsgeschichte there was little doubt about the correctness of Wissowa's view that the two groups of the diindigetes and the di novensides combined with each other represent the whole of theRoman pantheon, the di indigetes being the old, indigenous deities of the Roman people, inherited so to speak from the days of Romulus, the di novensides the new deities, imported in historical times from foreign peoples. This view has now been abandoned, owing to Altheim's arguments. Besides this, Altheim and later C. Koch have proved that the proximity of the expressions divi novensiles and di indigetes in Livy's report about the devotio of P. Decius Mus (viii. 9) does not in itself justify the conclusion that the di indigetes and the di novensides are linked together in such a manner that the solution of the problem of one group involves that of the other. Hence the questions arise, first, what is the nature of the di novensides or of the di indigetes, and whether either of these questions has been satisfactorily answered; secondly, is it possible to establish any relationship between these two groups of deities, and can such a relation be usedas a starting-point from which to investigate the nature of the other group? In choosing this line of research it seems to me that an attempt to solve the problem of the novensides rather than that of the indigetes promises greater success. I shall, therefore, treat the di novensides in the first part of this paper.