The 'Jefferson Duo' are the
fraternities of
Phi Gamma Delta and
Phi Kappa Psi.
[1] The fraternities were founded in
1848 and
1852, respectively, at Jefferson College in
Canonsburg,
Pennsylvania. A third fraternity, Kappa Phi Lamba (not to be confused with
Kappa Phi Lambda sorority), was also founded at Jefferson College but became extinct.
[2] In 1865, Jefferson College combined with Washington College to become
Washington and Jefferson College.
References
1. "North American College Fraternities: The 'Jefferson Duo'", pages 68-69. The Fraternity of Phi Gamma Delta Guide to Brotherhood. 2004
2. "North American College Fraternities: The 'Jefferson Duo'", page 69. The Fraternity of Phi Gamma Delta Guide to Brotherhood. 2004