Eighteen Years in Three Periods

Trent was demanded for twenty years before it met and then took eighteen years to finish, sitting in three widely separated periods under five popes, with a spell relocated to Bologna and long suspensions between. It was called too late to reunite anybody: by 1545 the Lutheran churches had confessional books and territorial establishments, and the council's effective task was to state what the Catholic Church held rather than to negotiate.

Its method shows in its results. On justification it produced a decree of real theological care, affirming that grace is prior and unmerited while refusing the formula that faith alone justifies, and its distinctions were argued over by good theologians for months. On scripture it declared the Latin Vulgate the authentic text for public use and set scripture and unwritten apostolic tradition side by side, against the Protestant appeal to scripture alone. On the sacraments it fixed the number at seven and defended the disputed practices of the mass, penance and the invocation of saints.

Its reforming legislation was as consequential as its doctrine. Bishops were required to reside in their dioceses, a rule widely ignored before, and every diocese was ordered to found a seminary for the education of its clergy. The professionalisation of the Catholic priesthood over the next century follows from that decree more than from any other.