So far as Babylonia was concerned, there was still in the twelfth century B.C.a city 'Der' which is called the 'city of Anu.' The city is probably of very ancient foundation, and its continued association with Anu forms an interesting survival of a local conception that appears to have been once current of the god.
In the religious literature, especially in that part of it which furnishes us with the scholastic recastings of the popular traditions, Anu is a much more prominent figure than in the historical texts.

From being merely the personification of the heavens, he is raised to the still higher dignity of symbolizing, as Jensen puts it,[170] the abstract principle of which both the heavens and earth are emanations.
All the earliest gods conceived of by popular tradition as existing from the beginning of things are viewed as manifestations of Anu, or of Anu and Anatum in combination.

He gives ear to prayers, but he is not approached directly.

The gods are his messengers, who come and give him report of what is going on.[171] He is a god for the gods rather than for men.

When his daughter Ishtar is insulted she appeals to her father Anu; and when the gods are terrified they take refuge with Anu.