Initially established as Greyson Students for Peace in 1968, Phi Beta Tau gradually evolved as the group's predominantly male membership adopted pacifist and feminist ideas, allied with a number of diverse civil rights groups, and generally became broader in scope. During this period, many of the group's female members had flocked to the increasingly liberal and genuinely charitable sorority of Sigma Zeta Chi, and the membership of GSP noticed that a distinctly conservative attitude lingered on at the root of the university's Greek system. Attempting to bring new liberal perspectives and more balance to the corrupt and outdated network, the members of GSP voted to dissolve their original organization, petition the Greek Council for the admittance of its male members (and, interestingly, some of the remaining female members) as the new Phi Beta Tau fraternity, and reform the external student organization as Students United for Peace and Justice.

Interestingly enough, the plan worked, and the new semi-co-ed fraternity of Phi Beta Tau began to thrive. Though it has yet to claim a house on Fraternitas Drive, the fraternity is increasingly well-liked, well-funded (with most of its treasury going to various charities and worthy causes) and popular among the progressively more and more liberal student body of Greyson University. Though it heartily encourages female pledges to check out Sigma Zeta Chi if they want a more 'traditional' sorority experience with a strong injection of liberal politics, Phi Beta Tau remains co-ed, with women making up around ten percent of its membership. It also openly welcomes GLBT members - and, honestly, rarely turns anyone away. Its 'pledging' process revolves around various activist efforts, with very little hazing and almost no emphasis on proving one's worthiness to enter the frat. In the Phi Betas' eyes, just about everyone is worthy.

Phi Beta Tau is most strongly associated with Sigma Zeta Chi; while this is an informal relationship and doesn't generally carry the romantic/sexual overtones of most of the fraternity/sorority affiliations on campus, the two orgs have become infamous for a phenomenon known on campus as a "Beta-Zeta marriage," in which a sister of Sigma Zeta Chi has a romantic partner (usually a girlfriend for a strict Beta-Zeta marriage, but sometimes a particularly unpretentious, sensitive and well-liked boyfriend) in Phi Beta Tau who unofficially lives with them in their room at the sorority house during the academic year. Though the administration isn't particularly thrilled with this sort of situation, the Sigma Zetas do own their house outright, so the university can't really do anything but look the other way and keep quiet about it.