Born into a Methodist family, he was for ten years a WM itinerant in the Midlands; but while stationed in the Wednesbury circuit was converted to Roman Catholicism by a local priest, Francis Martyn. He resigned from the ministry on 19 March 1819, was confirmed and ordained into the Catholic priesthood. Their discussions, centring on the nature of truth and the claims of tradition as the interpreter of Scripture, were described in his The Triumph of Truth in the Conversion of the Rev. J.A. Mason from the Errors of Methodism to the Catholic Faith (1827). In the same year he also published An Earnest Appeal to the People called Methodists and to the nation at large. During his ministry as a priest in Stourbridge Mason published other pamphlets, criticizing Wesley's understanding of Roman Catholicism as defective and misleading.