Eugen Bleuler, in 1911, renamed the group of mental disorders with poor prognosis which Emil Kraepelin had called "dementia praecox" "group of schizophrenias", because for him the splitting of personality was the main symptom. Biographical, scientific and methodological influences on Bleuler's concept of schizophrenia are shown with special reference to Kraepelin and Freud. Bleuler was a passionate and very experienced clinician. He lived with his patients, taking care of them and writing down his observations. Methodologically he was an empiricist and an eclecticist with a wide reading knowledge. In an impaired association of ideas, in disordered affectivity, in marked ambivalence and autism Bleuler saw the main symptoms of schizophrenia. For him these so-called pathological phenomena actually seemed to be only exaggerations of normal psychic functions. So there were only a quantitative, not a qualitative difference between schizophrenia and normal psychic processes and studies on schizophrenic "pathology"--seen as a disturbance, not as a disease--might analogously illustrate normal psychic reactions and vice versa. In etiology as well as in therapy Bleuler took into account psychological and (neuro)physiological (somatic) mechanisms--thus combining organicism and dynamic psychiatry and coming very close to modern concepts, e.g. the one of stress and vulnerability. Bleuler's main merit is the stressing on an idiographic "understanding" of the patient and a plausible and subtle explanation of schizophrenia which helped to reduce the alienation of the affected persons.