Rensselaer Polytechnic Institute has an extensive history of Greek community involvement on campus, including past presidents, honorary academic building dedications, and philanthropic achievements. The overall Greek system at Rensselaer stresses Leadership, Fortitude, Innovation, and Evolution. RPI currently has 29 active fraternities as well as 6 sororities, with 32 percent involvement of all males and 18 percent involvement of all females, organized under the Interfraternal Council and Panhellenic Council. Of those Greek organizations, three were founded at Rensselaer including the Theta Xi national engineering fraternity, the Sigma Delta Hispanic-interest local sorority, and the Rensselaer Society of Engineers local engineering fraternity. Theta Xi fraternity was established by RPI students on 29 April 1864, the only national fraternity founded during the Civil War. The Theta Xi Fraternity Chapter House is listed on the National Register of Historic Places. Additionally, Rensselaer is home to the Epsilon Zeta chapter of the Alpha Phi Omega, or "APO," national service fraternity, which operates a test-bank and office at the top floor of the Student Union. The organization also hosts a campus lost & found, universal can tab collection, and a public 3D printing service.