The Oedipus Complex is named after the character from a Greek tragedy who killed his father by mistake, and slept with his mother without realising who she was. Freud’s ideas on sexual development included the theory that boys reach a developmental stage when they lust after their mothers and that girls go through a similar stage, when they unconsciously fall in love with their fathers. For Freud, growing to psychological maturity for children involved experiencing and then getting beyond these Oedipus or Electra complexes. Edvard Westermarck saw it differently.