Knox College's Old Main—a national landmark and the only extant building that was a site of the Lincoln-Douglas debates—is a campus treasure with a secret. Built in 1857, Old Main was designed by Charles Ulricson, a Swedish-born immigrant who was trained by Freemasons. In Chapel in the Sky, Knox faculty member Lance Factor decodes the symbols of this beloved building and explores how an ardently Anti-Mason administration came to hire Ulricson. The mysterious Masonic architect left his legacy on both Knox's Old Main and the Augustana Lutheran Church in Andover, Illinois.Ulricson (1816–1887), born to an elite family in Stockholm, emigrated to the United States in 1835, arriving in New York City with empty pockets. Ulricson found work as a draftsman in the firm of Ithiel Town and Alexander Jackson Davis, America's premier antebellum architects and the leaders of the Greek, Gothic, and Tuscan revivals. From Davis, Ulricson learned that architects belonged to a "sacred priesthood." From Town, Ulricson learned the secret doctrines of "alchemical" architecture, its search for geometric philosopher's stones, and its techniques for drafting with a Masonic cubit and for transforming buildings into talismans, which they believed carried the protective energy of the Divine Architect and Geometer of the Universe.These lessons found expression in Ulricson's hidden codes for Old Main and Augustana Church. Ulricson's unique designs, rigorous geometry, elaborate windows, and interior decorations all contain tell-tale signs of Freemasonry. Ulricson essentially hid his symbols in plain sight of clients—vehement Anti-Masons who condemned all secret societies as "ungodly" and viewed all forms of alchemical architecture as "geomancy" or black magic. Chapel in the Sky explains how a dispossessed immigrant Masonic architect came to be the architect for the Anti-Masons, and how the meanings of his designs change our understanding of the architectural and ethnic history of Illinois. Factor's story will interest Knox alumni, architects, Freemasons, Swedish Americans, and those who love a tale of irony.