Pi Beta Phi (ΠΒΦ), often known simply as Pi Phi, is an international Fraternity for Women, founded at Monmouth College, in Monmouth, Illinois on April 28, 1867 as I.C. Sorosis, the first national secret college society of women to be modeled after the men’s Greek-letter fraternity. According to G. William Domhoff, in Who Rules America? (Seventh edition, p. 57), Pi Beta Phi was cited as one of the four or five sororities upper-class college women “joined with nationwide social prestige”.