Johann Christian August Heinroth

Johann Christian August Heinroth (17 January 1773 – 26 October 1843) was a German physician and psychologist who was the first to use the term psychosomatic.

Heinroth divided the human personality into three components in the 1800s, describing the Uberuns (conscience), the Ich (mind, emotions and will) and the Fleish (basic drives, which included man's sinful nature).

He initially studied medicine there, later continuing his education in Vienna under Johann Peter Frank (1745–1821).

His description of sin came from a 19th-century Protestant standpoint, and was also derived from an accepted European code of ethics and morality.

His definition of sin wasn't based on a singular event, but rather as a period of several years of an individual striving towards earthly, bodily satisfaction.