Texas A&M University has a student military organization called the Corps of Cadets, which is the oldest student organization on campus and was established with the university in 1876. While membership in the Corps of Cadets was mandatory for all students who attended Texas A&M until 1965, it is now voluntary. The Corps of Cadets is composed of three Air Force Groups, three Army Battalions, and three Navy/Marine units. All military branches are represented in the organization of the Cadet Corps. The men and women of the Corps of Cadets form the largest uniformed body of students outside of the United States service academies. Although Texas A&M commissions cadets into all five branches of service, most of them are commissioned through the three ROTC programs: Army, Navy (with a Marine Corps option), and Air Force.