During his 10 years as Regius Professor, a post once held by the great Sir William Osler, he helped develop one of the top medical schools in the world, with particular strengths in population-based studies of disease. Sir Richard taught medical students, practiced medicine, and conducted his research in the legendary Radcliffe Infirmary, where penicillin was first introduced to the world during World War II. He held this position until 1979 when he became the first Warden of Green College, and also Director of the Cancer Epidemiology Unit.