Following something Vered wrote I googled for mother goddess and ran across Semiramis, a legendary Assyrian queen-ruler who has the misfortune to owe a lot of her google-juice to the tireless efforts of Jack Chick style Christians, promoting a 19th century anti-Catholic propaganda which holds her responsible for inventing goddess-worship (and thus the Catholic cult of Mary).
Most entertaining seeing the edit wars in Wikipedia, where the Chick-ites keep replacing historical facts (as in, the actual legendary stuff made up about her by Roman historians) with biblical-literalist 19th century info.
The actual historical figure, Shammuramat, sounds like a fascinating and remarkable person, one of those rare queens who managed to exercise real political power in the name of her husband and son.
The legends are also pretty cool:
According to the legend as related by Diodorus, Semiramis was of noble parents, the daughter of the fish-goddess Derketo of Ascalon in Assyria and a mortal. Derketo abandoned her at birth and drowned herself. Doves fed the child until Simmas, the royal shepherd, found and raised her.
Derketo and Ascalun are names I ran across in the context of Bêlit from Conan, although I’m not sure if they came from Robert E. Howard or Roy Thomas.