One of the most famous Catholic converts of the nineteenth century (along with his friend, Orestes Brownson), Hecker founded the Paulist fathers in 1858.
Catholic Encyclopedia * Paulists
Diary Isaac T. Hecker, the Diary: Romantic Religion in Ante-Bellum America
L. Hostetter, The Ecclesial Dimension of Personal and Social Reform in the Writings of Isaac Thomas Hecker
D. O'Brien, Isaac Hecker: An American Catholic