This thesis is the story of the development of the Catholic Church in San Joaquin County and the adjacent areas that were served by the pioneer clergymen of Stockton 1 s St. Mary's Church from approximately 1851 to 186). These first dozen years of Central California Catholicism cover the pastorates of Stockton's first four priests: Fathers Dominic Blaive, Cornelius Delahunty, Robert Maurice, and Joseph Gallagher. These dozen years mark the transition of Stockton from a hectic supply center for the Southern Mines to a stable community whose economy became, based upon the agricultural production of its surrounding rural areas. These first four pastors, then, witnessed the development of the early American Catholic Church from its infancy as a mission when Abbe Blaive arrived in Stockton from his native France, to its maturity as a stable.and respected community church under the spiritual direction of the American, Father Joseph Gallagher.