But the conceptions which the Fathers of the Church had of the person and power of the devil, were still more changed when the German tribes overthrew the government of the Roman empire and adopted Christianity. In doing so this family of people did not lose the fullness of their own life, the highest manifestation of which was their old mythology. It is true that the names of the old gods gradually died away; what was obviously contrary to the new faith was at last set aside by the zeal of the priests, by force, and by pious artifices; but innumerable familiar shapes and figures, customs and ideas, were kept alive, nay, they not only were kept alive, but they entwined themselves in a peculiar manner with Christianity. As Christian churches were erected on the very spots where the heathen worship had been held, and as the figure of the crucified Saviour, or the name of an apostle was attached to sacred places like Donar's oak; thus the Christian saints and their traditions took the place of the old gods. The people transferred their recollections of their ancient heathen deities to the saints and apostles of the Church, and even to Christ himself, and as there was a realm in their mythology which was ruled by the mysterious powers of darkness, this was assigned to the devil. The name devil, derived from the Greek (diabolos), was changed into Fol, from the northern god Voland, his ravens and the raging nightly host were transferred to him from Wuotan, his hammer from Donar; but his black colour, his wolves or goat's form, his grandmother, the chains wherewith he was bound, and many other traditions, he inherited from the evil powers of heathendom which had ever been inimical to the benevolent ruling gods. These powerful demons, amongst whom was the dark god of death, belonged according to the heathen mythology to the primeval race of giants, which as long as the world lasted were to wage a deadly struggle with the powers of light. They formed a dark realm of shapeless primordial powers, where the deepest science of magic was cultivated. To them belonged the sea-serpent, which coiled round the earth in mighty circles, lay at the bottom of the ocean, the giant wolves which lay fettered in the interior of the earth or pursued the sun and moon, by which, at the last day, they were to be destroyed; the ice demons which from the north sent over the land snow-storms and devastating floods; and worse than all, the fiendish Helia, goddess of the dead. Besides the worship of the _Asengoetter_, there was in heathen Germany a gloomy service for these demons, and we learn from early Christian witnesses that even before the introduction of Christianity, the priestesses and sorcerers of these dark deities were feared and hated. They were able by their incantations to the goddess of death, to bring storms upon the corn-fields and to destroy the cattle, and it was probably they who were supposed to make the bodies and weapons of warriors invulnerable.