John R. Slattery

Slattery worked for years in the mission field, establishing parishes, schools, and other ministries on behalf of the society. Among these were St. Joseph's Seminary for graduate students studying to become Josephites, and Epiphany Apostolic College, a minor seminary for the order. Both schools educated several of the first African-American Catholic priests in history, including Charles Uncles.

Among his various pursuits, Slattery also collaborated with prominent lay Black Catholics. Among these were Daniel Rudd, the founder of the nation's first Black Catholic newspaper, the American Catholic Tribune, and the Colored Catholic Congress. Slattery was heavily involved in both pursuits, before a falling out led to his withdrawal of support.

After years of struggle against racism both in and outside the Catholic Church, including vehement opposition to his goal of ordaining African Americans to the Catholic priesthood, Slattery left the Josephites and the Church in 1906 before marrying and becoming outspokenly anti-Catholic.

A lawyer by trade from then until his death on March 6, 1926, his fortune and papers were left to the New York Public Library.