 Expansion remained dormant throughout World War II as many fraternity members served in the war effort.With the end of the war and the shift of the national headquarters to St. Louis, Alpha Epsilon Pi had gained new life and momentum in its reopening of inactive chapters, expansion to new campuses, and the merging with other locals that had seen reduced membership as a result of the war.In 1940, Sigma Omega Psi joined Alpha Epsilon Pi adding three chapters, as did Sigma Tau Phi in 1947.