Carl Gustav Jung (1875-1961), Swiss psychiatrist and one of the founders of modern analytical psychotherapy. In 1907, Jung met Sigmund Freud and became his main collaborator. He served as the first president of the International Psycho-Analytical Association until 1912, when he and Freud broke up. Jung felt that sexual causes of neuroses were minimal, but continued to champion the role of the unconscious mind. He believed that as well as a 'personal unconscious' formed by a person's experiences, there was also a 'collective unconscious' which was common to all humanity.