The sun-god of Heliopolis was represented, like the gods of Babylonia, as a man and not as a hawk. He was known as Tum or Atmu, who, in the later days of religious syncretism, was distinguished from the other forms of the sun-god as representing the setting sun. But Tum was the personal name of the sun-god; the sun itself was called Ra. As time went on, the attributes of the god were transferred to the sun; Ra, too, became divine, and, after being first a synonym of Tum, ended by becoming an independent deity. While Tum was peculiarly the setting sun, Ra denoted the sun-god in all his forms and under all his manifestations. He was thus fitted to be the common god of all Egypt, with whom the various local sun-gods could be identified, and lose in him their individuality. Ra was a word which meant “the sun” in all the dialects of the country, and its very want of theological associations made it the starting-point of a new phase of religious thought. It was not until the rise of the Twelfth Dynasty that a special temple was built to Ra in Heliopolis.(52) Up to that time Ra had been content to share with Tum the ancient temple of the city, or rather had absorbed Tum into himself and thus become its virtual possessor. But his religious importance goes back to prehistoric times. The temple of Heliopolis became the centre of a theological school which exercised a great influence on the official religion of Egypt. It was here that the sun-worship was organised, and the doctrine of creation by generation or emanation first developed; it was here, too, that the chief gods of the State religion were formed into groups of nine.(53) The doctrine of these Enneads or groups of nine was destined to play an important part in the official creed. From Heliopolis it spread to other parts of Egypt, and eventually each of the great sanctuaries had its own Ennead, formed on the model of that of Heliopolis. At Heliopolis the cycle of the nine supreme gods contained Shu and Tefnut, Seb and Mut, Osiris and Isis, Set and Nebhât, the four pairs who had descended by successive acts of generation from Tum, the original god of the nome. We owe the explanation and analysis of the Ennead to Professor Maspero, who has for the first time made the origin of it clear.(54)