| Tradition and Authority in the Western Church, 300-1140 Beginning with the conversion of Constantine in 312 and the establishment of the Christian Empire, the book continues through the Middle Ages up to the publication of Gratian's Decretum , the great, systematic book of Church law which transformed the idea of tradition into legal concepts. Throughout this period the hierarchy was called upon to deal with such fundamental questions as the nature of tradition and the extent of its authority, the infallibility of the pope, and the proper role of the laity in defining dogma. |