The Athenaeum of Ohio – Mount St. Mary's Seminary of the West, originally St. Francis Xavier Seminary is a Roman Catholic seminary in Cincinnati, Ohio. It is the third-oldest Catholic seminary in the United States. It was established by Bishop Edward D. Fenwick, the first Bishop of Cincinnati, in 1829[2] along with The Athenaeum (later Xavier University and St. Xavier High School), which opened in 1831 in downtown Cincinnati.