It is argued that Freud’s analysis of Sophocles’ Oedipus Rex should be read in the context of his Interpretation of Dreams. There it figures in the chapter on typical dreams of the death of beloved persons, dreams from which Freud infers a murderous desire directed to the father. Later, Freud admitted that this view involved his own reaction to the death of his father. For Freud, the latter constitutes the most importance experience in a man’s life. From then onwards however, the theme of the murder of the father is revealed as a fantasm that hides the castration of the father with which the son is confronted when his own father dies. With reference to the hellenistic commentaries on Oedipus Rex, a Lacanian interpretation of the tragedy is proposed. It is argued that Oedipus Rex is the tragedy of the subject and his responsibility when Mythical discourse was replaced by the Master discourse, in which the Master figures both as father of a castrated reality and as mythical father who escapes castration. Castration consists precisely of the loss of jouissance introduced by the Master discourse. Eventually it is argued that, for Lacan, the castration complex comes down to the truth of the Oedipus complex.