The painting depicts Oedipus meeting the Sphinx at the crossroads on his journey between Thebes and Delphi. Oedipus must answer the Sphinx's riddle correctly in order to pass. Failure means his own death and that of the besieged Thebans. 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...