In psychoanalytic theory, the id, ego, and superego are three distinct, interacting agents in the psychic apparatus, outlined in Sigmund Freud's structural model of the psyche. The three agents are theoretical constructs that Freud employed to describe the basic structure of mental life as it was encountered in psychoanalytic practice. Freud himself used the German terms das Es, Ich, and Über-Ich, which literally translate as "the it", "I", and "over-I". The Latin terms id, ego and superego were chosen by his original translators and have remained in use.