Oedipus complex desire (libido) for mother, and aggression towards father, student–collaborator Carl Jung counter-proposed that girls experienced desire for father and aggression towards mother via the Electra complex—derived from the 5th-century BC Greek mythologic character Electra, who plotted matricidal revenge with Orestes, her brother, against Clytemnestra, their mother, and Aegisthus, their stepfather, for their murder of Agamemnon, her father (cf. "Electra", by Sophocles). Moreover, because it is native to Freudian psychology, orthodox Jungian psychology uses the term "Oedipus complex" only to denote a boy's psychosexual development. In classical Freudian psychology the super-ego, "the heir to the Oedipus complex", is formed as the
Oedipus and the Sphinx 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 first to answer the riddle correctly and, having heard Oedipus' answer, the Sphinx was astounded and inexplicably killed herself by throwing herself into the sea. Oedipus thereby won the freedom of the Thebans, the kingdom of that city