The Council of Trent was a major event in the history of Christianity. It shaped Roman Catholicism's doctrine and practice for the next four hundred years and continues to do so today. The literature on the Council is vast and in numerous languages. This Companion, written by an international group of leading researchers, brings together the latest scholarship on the principal issues treated at the Council: the relationship between Scripture and Tradition, original sin, justification, the sacraments (Baptism, Penance, Confirmation, Eucharist, Holy Orders, Marriage, and the Annointing of the Sick), sacred images, sacred music, and its reform of religious orders, the training of the clergy, the provision of pastoral care in the parish setting, and the implementation of its decrees. The volume demonstrates that the Council unwittingly furthered the papal centralization of authority by allowing the interpretation of its decrees to be the exclusive prerogative of the Holy See, and entrusting it with their implementation.