Which Greek hero solved the riddle of the Sphinx?

Oedipus solved the riddle of the Sphinx and thereby freed Thebes from the monster’s deadly challenge.

According to the best-known version of the myth, the Sphinx stopped travelers outside Thebes and killed those who could not answer her riddle. The riddle described a creature that walked on four legs in the morning, two at midday, and three in the evening. Oedipus answered “man”: a baby crawls on all fours, an adult walks upright, and an elderly person may use a staff.

The Sphinx was defeated after Oedipus supplied the answer; traditions differ on whether she killed herself or was killed by Oedipus. His reward was the throne of Thebes and marriage to the widowed queen Jocasta. The later revelation that Jocasta was his mother fulfilled a terrible prophecy and drove the rest of the tragedy. The exact riddle is not stated in Sophocles’ Oedipus Rex and was standardized in later retellings.