Robert Graves[19] considered Tiamat's death by Marduk as evidence of his hypothesis that a shift in power from a matriarchy controlling society to a patriarchy happened in the ancient past. Grave's ideas were later developed into the Great Goddess theory by Marija Gimbutas, Merlin Stone and others. The theory suggests Tiamat and other ancient monster figures were presented as former supreme deities of peaceful, woman-centered religions that were turned into monsters when violent.