According to some traditions within Mesopotamian belief, Nammu was the primeval mother goddess who gave birth to An (heaven) and Ki (earth), as well as to several other primeval deities. Nammu was particularly identified as the mother of Enki/Ea, lord of the Abzu, the vast freshwater ocean thought to lie beneath the Earth. Indeed, the name of Nammu was written in cuneiform script with the same sign as engur – a synonym of Abzu – suggesting that she was thought of as a personification of this subterreanean ocean, the domain of her son.