Amphitrite (am-fi-TRY-tee). A daughter of Nereus, the Old Man of the Sea. King Minos once challenged Theseus to prove that he was a son of the god Poseidon, supreme ruler of the watery depths. Minos took a ring from his finger and threw into the sea, daring Theseus to dive down and retrieve it. Not only did the hero succeed in this task, but while he was underwater he came upon a palace where Amphitrite (or her sister Thetis) presented him with a jeweled crown.