Quote:
Originally Posted by MysticCat
Along "org" out, along with Delta Zeta. 
Beta Theta Pi, Phi Delta Theta and Sigma Chi are grouped together as the Miami Triad both because they were founded in roughly the same timeframe (1839-55, versus 1906 for Phi Kappa Tau), and because, like the Union Triad, they had a significant influence on the development of the fraternity system in a way that orgs founded much later (20th century) did not. |
I would just add that the main thing about The Miami Triad is that all three were expansion-oriented fraternities pretty much from the get go.