Most of the Celtic divinities were local in character, each tribe possessing its own group, each god having functions similar to those of other groups. Some, however, had or gained a more universal character, absorbing divinities with similar functions. Still this local character must be borne in mind. The numerous divinities of Gaul, with differing names--but, judging by their assimilation to the same Roman divinity, similar functions, are best understood as gods of local groups. This is probably true also of Britain and Ireland. But those gods worshipped far and wide over the Celtic area may be gods of the undivided Celts, or gods of some dominant Celtic group extending their influence on all sides, or, in some cases, popular gods whose cult passed beyond the tribal bounds. If it seem precarious to see such close similarity in the local gods of a people extending right across Europe, appeal can be made to the influence of the Celtic temperament, producing everywhere the same results, and to the homogeneity of Celtic civilisation, save in local areas, e.g. the South of Gaul. Moreover, the comparison of the various testimonies of onlookers points to a general similarity, while the permanence of the primitive elements in Celtic religion must have tended to keep it everywhere the same. Though in Gaul we have only inscriptions and in Ireland only distorted myths, yet those testimonies, as well as the evidence of folk-survivals in both regions, point to the similarity of religious phenomena. The Druids, as a more or less organised priesthood, would assist in preserving the general likeness.
Thus the primitive nature-spirits gave place to greater or lesser gods, each with his separate department and functions. Though growing civilisation tended to separate them from the soil, they never quite lost touch with it. In return for man's worship and sacrifices, they gave life and increase, victory, strength, and skill. But these sacrifices, had been and still often were rites in which the representative of a god was slain. Some divinities were worshipped over a wide area, most were gods of local groups, and there were spirits of every place, hill, wood, and stream. Magic rites mingled with the cult, but both were guided by an organised priesthood. And as the Celts believed in unseen gods, so they believed in an unseen region whither they passed after death.