Carroll was a Catholic. Maryland was the first among the colonies to provide for freedom of religion, having been founded for this purpose by the Catholic Lord Baltimore (the Calvert family) in 1632.
Only about 50 years before that, it was a crime to be a Catholic priest in England, and many people were subjected to the truly “cruel and unusual punishment” of drawing and quartering for that offense. One of the great gifts of the United States to the world was the concept of disestablishment of religion, which made religion a matter of individual conscience.