Animal worship pure and simple had declined among the Celts of historic times, and animals were now regarded mainly as symbols or attributes of divinities. The older cult had been connected with the pastoral stage in which the animals were divine, or with the agricultural stage in which they represented the corn-spirit, and perhaps with totemism. We shall study here (1) traces of the older animal cults; (2) the transformation of animal gods into symbols; and (3) traces of totemism.
The presence of a bull with three cranes (Tarvos Trigaranos) on the Paris altar, along with the gods Esus, Juppiter, and Vulcan, suggests that it was a divine animal, or the subject of a divine myth. As has been seen, this bull may be the bull of the Tain bo Cuailgne. Both it and its opponent were reincarnations of the swine-herds of two gods. In the Irish sagas reincarnation is only attributed to gods or heroes, and this may point to the divinity of the bulls. We have seen that this and another altar may depict some myth in which the bull was the incarnation of a tree or vegetation spirit. The divine nature of the bull is attested by its presence on Gaulish coins as a religious symbol, and by images of the animal with three horns—an obvious symbol of divinity. On such an image in bronze the Cimbri, Celticised Germans, swore. The images are pre-Roman, since they are found at Hallstadt and La Tene. Personal names like Donnotaurus (the equivalent of the Donn Taruos of the Tain) or Deiotaros ("divine bull"), show that men were called after the divine animal. Similarly many place-names in which the word taruos occurs, in Northern Italy, the Pyrenees, Scotland, Ireland, and elsewhere, suggest that the places bearing these names were sites of a bull cult or that some myth, like that elaborated in the Tain, had been there localised. But, as possibly in the case of Cuchulainn and the bull, the animal tended to become the symbol of a god, a tendency perhaps aided by the spread of Mithraism with its symbolic bull. A god Medros leaning on a bull is represented at Haguenau, possibly a form of Mider or of Meduris, a surname of Toutatis, unless Medros is simply Mithras. Echoes of the cult of the bull or cow are heard in Irish tales of these animals brought from the sid, or of magic bulls or of cows which produced enormous supplies of milk, or in saintly legends of oxen leading a saint to the site of his future church. These legends are also told of the swine, and they perhaps arose when a Christian church took the place of the site of a local animal cult, legend fusing the old and the new cult by making the once divine animal point out the site of the church. A late relic of a bull cult may be found in the carnival procession of the Boeuf Gras at Paris.