This fonds principally contains records connected with the Congregation of St. Basil (Basilian Fathers) whose members administered Assumption College and Assumption University from 1870 onward. Secondarily, it contains varied records that document the history of Assumption and its evolution over time. Included are legal documents, memos, correspondence, ephemera, constitutions and rules, historical narratives and memoirs, reports, and a variety of Basilian publications and formal histories of Assumption. Some items pertain to Catholic education broadly, or to the history of the Catholic Church in Southwestern Ontario. Of special note are Assumption fight songs and a victory song, and the Second World War war diary of Rev. Mike Dalton, a military chaplain.

This fonds primarily contains personal papers, publications, and oral histories (ca. 1870-1984) relating to the Basilian Fathers who served as teaching staff for Assumption College and Assumption University. Included are diaries, notebooks, correspondence, memoirs, recorded interviews, memorials, manuscripts and published works. Of special note are the extensive papers of Bishop Leo C. Nelligan, records of O’Connor House, and a few records from Rev. Pierre Tourvieille. Secondarily, this fonds contains extensive administrative records documenting the history of Essex College, found in the papers of professor W.H. Arison.