Delta Upsilon was founded in 1834, when thirty freshman, sophomore, and junior students at Williams College met in the Freshman Recitation Room at the West College building to form what was then called "the Social Fraternity". The move was in response to the establishment of Kappa Alpha and Sigma Phi at the college and, unlike those fraternities, the Social Fraternity was avowedly anti-secret. Its founding came at the tail-end of the anti-Masonic hysteria that had recently swept the United States, though the idea that it was part of the popular backlash to Freemasonry has generally been rejected (a mysterious fire in 1841 destroyed the records of the first meeting of the Social Fraternity, erasing much of the organization's early history).