 Sir William Osler became the first Professor of Medicine at Johns Hopkins and the first Physician-in-Chief at the Johns Hopkins Hospital.Osler was responsible for establishing the "residency" system of postgraduate medical training, where young physicians were required to "reside" within the hospital to better care for their patients.Upon matriculation, medical students at the Johns Hopkins School of Medicine are divided into four Colleges named after famous Hopkins faculty members who have had an impact in the history of medicine (Florence Sabin, Vivien Thomas, Daniel Nathans and Helen Taussig).