The Prophecy

Despite being wed to Hera, Zeus had several relationships with both immortals and humans. Zeus cherished aesthetic beauty. The sea nymph Thetis was lovely. Zeus inevitably felt a pull for her and desired to wed her. He was well aware, nevertheless, that his father Cronus had deposed Uranus and that Zeus had cunningly taken his position. He learned of the prophecy that he would be deposed by his successor, who would be more powerful than himself, much later from Themis or Prometheus.

He was also disappointed to learn that another prophecy predicted that a son of Zeus and Thetis' union would likewise bring about his ultimate destruction. Zeus became terrified and decided to modify their marriage to alter the prophecy. As a result, it leaves him defenseless and serves as one of the major causes of the Great Trojan War.