Tum, who is always represented in human form, was the ancient sun-god and tutelary deity of Heliopolis. To him was ascribed the creation of the world, just as it was ascribed by each of the other nomes to their chief god. But whereas at the Cataract the creator was a potter who had made things from clay, or at Memphis an artist who had carved them out of stone, so it was as a father and generator that Tum had called the universe into being. In the Book of the Dead it is said of him that he is "the creator of the heavens, the maker of (all) existences, who has begotten all that there is, who gave birth to the gods, who created himself, the lord of life who bestows upon the gods the strength of youth." An origin, however, was found for him in Nu, the primeval abyss of waters, though it is possible that Professor Maspero may be right in thinking that Nu really owes his existence to the goddess Nut, and that he was introduced into the cosmogony of Heliopolis under the influence of Asiatic ideas. However this may be, Shu and Tefnut, who immediately emanated from him, apparently represented the air. Later art pictured them in Asiatic style as twin lions sitting back to back and supporting between them the rising or setting sun.(55) But an old legend described Shu as having raised the heavens above the earth, where he still keeps them suspended above him like the Greek Atlas. A text at Esna, which identifies him with Khnum, describes him as sustaining "the floor of the sky upon its four supports" or cardinal points; "he raised Nut, and put himself under her like a great column of air." Tefnut, his twin sister, was the north wind, which gives freshness and vigour to the world.
The next pair in the Ennead of Heliopolis were Seb and Nut, the earth and the firmament, who issued from Shu and Tefnut. Then came Osiris and Isis, the children of the earth and sky, and lastly Set and Nebhât, the one the representative of the desert land in which the Asiatic nomads pitched their tents, the other of the civilised Egyptian family at whose head stood _Neb-hât_, "the lady of the house." Upon the model of this Ennead two other minor Enneads were afterwards formed.
But it was only its first father and generator who was the god of the nome in which the temple of Heliopolis stood. The deities who were derived from him in the priestly cosmogony were fetched from elsewhere. They were either elementary deities like Shu and Seb, or else deities whose worship had already extended all over Egypt, like Osiris and Isis. The goddess Nebhât seems to have been invented for the purpose of providing Set with a sister and a consort; perhaps Tefnut, too, had originally come into existence for the same reason.