Danu (or Anu) is one of the oldest Goddesses of the Celts. The Celts had numerous Gods and Goddesses (they believed that most things in the natural world contained spirits).
The Celts embraced a creation myth. That is, they embraced a belief structure to explain the existence of the natural and supernatural worlds. Danu was central to the creation myth. In one version, she is the fountain for all other Gods/Goddesses. She was thought to have emerged from the tree of life (the tree of life is often depicted on jewelry, cups, shirts and the like) in the form of a river (the Danube for many believers), which in turn gave birth to other spirits. Thus, she is considered to be a goddess of fertility.
