Continuing his journey to Thebes, Oedipus encountered a Sphinx, who would stop all travelers to Thebes and ask them a riddle. If the travelers were unable to answer her correctly, they would be killed and eaten; if they were successful, they would be free to continue on their journey. The riddle was: "What walks on four feet in the morning, two in the afternoon and three at night?". Oedipus answered: "Man: as an infant, he crawls on all fours; as an adult, he walks on two legs and; in old age, he uses a 'walking' stick". Oedipus was the first to answer the riddle correctly and, the Sphinx allowed him to continue on.