Eta Nu Chapter was chartered on May 14, 1956. Its founder was Brother Hermes Paul Turner FSC ('46), who started the chapter as a way to bring together the members of the MariNotes (big band), and the SMC Glee Club. Brother Hermes Paul was the director of both groups, and members of these groups participated jointly in such activities as the Redman Revels, an all-campus variety show that predated the current Blue Angel and Gaslight shows. At the time of the chartering of the chapter, Saint Mary's College enrolled only male students and there was no music department. Brother Paul's membership certificate still hangs in the fraternity room, with the date of the founding of the chapter, as a memento of the beginning of Sinfonia at Saint Mary's.