What a Council Can Actually Fix

Trent met in sessions across eighteen years, and its output divides neatly into doctrine and plumbing. On doctrine it restated the disputed positions in terms designed to exclude the Protestant readings: justification as a process involving cooperation rather than a single imputed act, seven sacraments, the real presence defined in the language of transubstantiation, and a fixed canon of scripture including the books Protestants placed outside it. On plumbing it did something arguably more consequential. It required every diocese to found a seminary, because a great deal of the criticism directed at the clergy concerned men who had been ordained without training. It required bishops to live in their dioceses, which many had not. It regulated the appointment of parish clergy, the keeping of registers and the conduct of visitation.

Diarmaid MacCulloch's history of the whole period observes that the discipline outlasted the polemic. Doctrinal formulas are argued about for centuries, but a rule that every priest must pass through a seminary changes what the clergy of a church are like within two generations, and the Catholic parish priest of 1650 was a recognisably different figure from his predecessor of 1500 largely for that reason.