This paper wishes to draw attention to a phenomenon which is of equal importance to the historian of art as to the ecclesiastical historian. In correlating facts which are largely known, it tries to explain the emergence of a new type of illustrated bible at the end of the eleventh century, chiefly in France and in Italy. These giant bibles, usually in more than one volume, were obviously not made for an individual reader who studied the bible in private. Their large size, as well as the richness and content of their decoration, indicate that they were conceived as visual symbols of the authority, the history, and the structure of the Church as an institution, as revealed in the Old and the New Testament. The origin of this new type of illustrated bible is closely connected with the Reform of the eleventh century, and it appears first in the diocese of Rheims, though its example was followed rapidly throughout western Europe.