Theta Xi was founded on April 29, 1864 at Rensselaer Polytechnic Institute in
Troy, New York as an engineering fraternity. Its founders were
George Bradford Brainerd, Samuel Buel Jr., Henry Harrison Farnum, Peter Henry Fox, Ralph Gooding Packard, Thomas Cole Raymond, Nathaniel Henry Starbuck, and Christopher Champlin Waite. Beginning in 1999, Theta Xi began offering Leadership academies to its active brothers. That year, the first President's Academy was held to train new chapter presidents, funded by the Theta Xi Foundation. In 2006, this was expanded to include Rising Stars Academy, which aims to make first-year initiates more active in the fraternity. In 2014, Theta Xi celebrated its sesquicentennial. In honor of this occasion, the National Convention was held in Troy, New York to commemorate the founding of Theta Xi. William S. Mason, considered to be one of the greatest benefactors and supporters of Theta Xi, was the main supporter of the fraternity's adoption of
Benjamin Franklin as its patron saint. Although the fraternity had been headquartered in St. Louis since 1924, on October 3, 2022, it opened new headquarters at 260 Peachtree Street in
Atlanta with the address for the Theta Xi Foundation remaining in St. Louis. == Purpose ==