Frazer attempted to define the shared elements of religious belief and scientific thought, discussing fertility rites, human sacrifice, the dying god, the scapegoat, and many other symbols and practices whose influences had extended into the 20th-century culture. His thesis is that old religions were fertility cults that revolved around the worship and periodic sacrifice of a sacred king. Frazer proposed that humanity progresses from magic through religious belief to scientific thought.
Frazer's thesis was developed in relation to J. M. W. Turner's painting of The Golden Bough, a sacred grove where a certain tree grew day and night. It was a transfigured landscape in a dream-like vision of the woodland lake of Nemi, "Diana's Mirror," where religious ceremonies and the "fulfillment of vows" of priests and kings were held.
The king was the incarnation of a dying and reviving god, a solar deity who underwent a mystic marriage to a goddess of the Earth. He died at the harvest and was reincarnated in the spring. Frazer claims that this legend of rebirth is central to almost all of the world's mythologies.