The Yale Graduate School of Arts and Sciences is the graduate school of Yale University. Founded in 1847, is the oldest graduate school in North America, and was the first North American graduate school to confer the degree of Doctor of Philosophy (Ph.D.). The Graduate School enrolls approximately 2,800 students, one-third of whom come from outside the United States. Approximately 900 faculty are involved with the graduate students as teachers, mentors, and advisors. Most of these faculty also teach in Yale College, the undergraduate school of the university.