The cult of Set was of the greatest antiquity, and although in later times he was regarded as evil personified, this was not his original _rôle_. According to the priests of Heliopolis he was the son of Geb and Nut, and therefore brother of Osiris, Isis, and Nephthys, husband of the latter goddess and father of Anubis. These relationships, however, were all manufactured for him at a comparatively late period. In the Pyramid Texts we find Set acting as a friend to the dead, and he even assisted Osiris to reach heaven by means of a ladder. He is also associated with Horus and is regarded as his equal. But in time they came to be regarded as mortal enemies, who were only prevented from entirely destroying one another by the wise Thoth. Horus the Elder was the god of the sky by day, and Set the god of the sky by night. The one was in fact the direct opposite of the other. The derivation of the name Set presents many difficulties of elucidation. The determinative of his hieroglyph is either the figure of an animal or a stone, which latter seems to symbolize the stony or desert country on either side of the Nile. As to the animal which pictorially represents him, it has by no means been identified, but various authorities have likened it to a camel and an okapi. In any case it must have been a denizen of the desert inimical to man. As Horus was the god of the North, so was Set god of the South. Dr. Brugsch considered Set symbolized the downward motion of the sun in the lower hemisphere, thus making him the source of the destructive heat of summer. As the days began to shorten and the nights to lengthen it was thought that he stole the light from the sun-god. He was likewise instrumental in the monthly destruction of the moon. Storms, earthquakes, and eclipses and all natural phenomena which caused darkness were attributed to him, and from an ethical point of view he was the god of sin and evil.