The Greatmother or The horned goddess was the feminine principle of space, the feminine face of the male-female-neuter trinity accepted as Supreme Being by many religions within the Imperium.
She was called Kubebe on Ix, Hawt on Humidis, Venera on Gamont and Serite on the worlds of the Wallach Group. The Zensunni spoke of Auliya, the female at the left hand of God or God's handmaiden and during the reign of Leto Atreides II the ancient Isis-Cult reemerged. Other names and titles applied to her included Gaea, Kali, Urania, Earth Mother, the maternal link between heavenly and earthly worlds, Dark Lady, the Priestess of Night and the Queen and Mistress of the Realm of No Return.
Like the many faces of a foretold messiah, Mahdi or other savior-figures, who fulfilled the role of paving the ground for the coming of the Kwisatz Haderach, the goddess cults were secretly supported and usurped by the Bene Gesserit to strengthen the matriarchial doctrine of their order and their supposed forthbringing of the Kwisatz Haderachs Mother from among their sisters.
After the Atreides Empire the many goddess-cults fell apart again or gave rise to sects such as the Cult of Alia or the Cult of Sheeana.