Penn has four undergraduate schools as well as twelve graduate and professional schools. Schools enrolling undergraduates include the College of Arts and Sciences, the School of Engineering and Applied Science, the Wharton School, and the School of Nursing. Penn's "One University Policy" allows students to enroll in classes in any of Penn's twelve schools. Among its highly ranked graduate and professional schools are a law school whose first professor wrote the first draft of the United States Constitution, the first school of medicine in North America (Perelman School of Medicine, 1765), and the first collegiate business school (Wharton School, 1881).