Phillips Academy, at Andover, Mass.; college preparatory boarding and day school; opened 1778, chartered 1780 by Samuel Phillips. Founded for boys, it is the oldest incorporated academy in the United States and has served as the model for many later schools. In 1972 the academy became coeducational when Abbot Academy, a neighboring girls' school, was incorporated. The school is often called Andover or Phillips Andover. Andover Theological Seminary (now part of Andover Newton Theological School at Newton Centre, Mass.) was affiliated from 1808 to 1908. The Addison Gallery of American Art houses well-known collections.