In the childhood of the Earth men long lived in a golden age of unbroken peace, knowing of no evil. But there came a time when two beings among the giants, both adopted by the Gods as members of the Asgard family, appeared among men tempting them to evil things, the man Loke, and the woman Gullveig (the golden way, or stream), Gullveig being the worse. To strengthen the good in human hearts, enlighten them and prepare them for coming days of strife, the Gods sent to Midgard as Teacher Heimdall, the Shining One, the God of the pure and most sacred fire. He brought with him many things not before seen in Midgard, and as the ruler of the people he instructed them in cultivating the soil, in sowing the seed he had brought, and in preparing bread; in carving and forging, spinning and weaving, cutting runes and reading. He taught them how to tame animals for domestic use, to build houses and to form families and communities; also the use of weapons in protection against animals. And further he informed them of the rules laid down by the Norns for a righteous life, and of the names and functions of the Gods. He showed them how to build altars and temples for worship, and brought to them the pure and undefiled fire produced by friction, the only one worthy of burning in the shrine of the Gods; and then he taught them the sacred songs that ever since have sounded from the lips of men in praise of divine powers. But even now Gullveig began her wanderings among men and secretly taught them runes and songs which counteracted Heimdall's teachings. When the Gods became aware of this, they had her burned; but her heart was proof against fire. Loke found it, and swallowing it he brought into the world the monster-wolf Fenris, which feeds on all the evil thoughts and feelings among men. Gullveig soon incarnated again and continued her ways unrecognized for a long period. When discovered she was burned a second time, Loke again finding her heart and giving life to the giantess of pestilence, Leikin. The same thing happened a third time, and then was born the Midgard-Snake, destined to grow rapidly and finally to encircle the whole earth.