Phi Sigma Epsilon (ΦΣΕ) was a North American social fraternity that operated for 75 years (February 20, 1910 – August 14, 1985) until its merger with the Phi Sigma Kappa (ΦΣΚ) fraternity. In 1985, the majority of Phi Sigma Epsilon chapters participated in the merger. Phi Sigma Kappa incorporated many of the symbols of Phi Sigma Epsilon into its own, changing its crest, and expanding its Cardinal Principals, symbolism, rituals, and historical canon to embrace the milestones of Phi Sigma Epsilon's development. These changes were soon fully adopted by all chapters of the fraternity which retained the name Phi Sigma Kappa.