ANU.  In Assyrian mythology the first great deity of the upper triad, Anu, Elu or Bel, and Hea, or Heaven, Earth, and Hades.  His residence was in the upper or seventh heaven, which was called the heaven of Anu, and was symbolized by an emblem resembling a Maltese cross, which was often worn round the necks of the Chaldean kings.  As the god of heaven, he was called "The God of Heaven," "Anu the King, The Great God, The god of the World, The Chief of the Gods, and Father Anu."  The Assyrians regarded him more in the light of the Zeus of the Greeks as a divine and benevolent personality.  The Accadians, on the other hand, looked upon him simply as the Spirit or fetisch of Heaven, in which case he was called Anna, or still more simply Na.  His wife Anatu, was simply a feminine form of himself.  She was the goddess of life and death, and the Anaitis of the Egyptians. (An Archaic Dictionary, Cooper, 1876).

... Prior to the time that the city of Ashur assumed the role of mistress of the northern district, Anu stood at the head of the pantheon, just as theoretically he continued to occupy this place in the pantheon of the south.  What is especially important, he had a temple in the very city of Ashur, whose patron god succeeded in usurping the place of the old "god of heaven."  The character of Anu in the north differs in no way from the traits assigned to him in the south.  He is the king of the Igigi and Anunnaki, that is, of all the heavenly and earthly spirits, and he is this by virtue of being supreme god of heaven.  His cult, however, appears to have suffered through the overshadowing supremacy of Ashur.  Even in his old temple at Ashur, which Tiglathpileser I. on the occasion of his rebuilding it, tells us was founded 641 years before this restoration, he is no longer accorded sole homage.  Ramman, the god of thunder and of storms, because correlated to Anu, is placed by the side of the latter and permitted to share the honors with Anu.  Anu survives in the Assyrian as in the Babylonian pantheon by virtue of being a member of the theological triad, composed as we have seen of Anu, Bel, and Ea.  Tiglathpileser I. still invokes Anu as a deity of practical importance.  He associates him with Ramman alone, but beyond an incidental mention by Ashurnasirbal, who in a long list of gods at the beginning of his annals emphasizes the fact of his being the favorite of Anu, he appears only in combination with Bel and Ea.  The same degree of reverence, however, was shown to the old triad in Assyria as in Babylonia.  The three gods are asked not to listen to the prayers of the one who destroys the monuments set up by the kings.  Sargon tells us, that it is Anu, Bel, and Ea who fix the names of the months, and this same king when he comes to assign names to the eight gates of his great palace, does not forget to include Anu in the list of deities, describing him as the god who blesses his handiwork... (Religion of Babylonia & Assyria, Jastrow, 1898)