The essay endorses the efforts of the French Annalist school, especially the recent interest in the history of “mentalities.” In terms of medieval historiography, it urges, however, that much closer attention be given to the religious mentality of medieval people which was decisively shaped by the symbolism of the Bible and the history of its interpretation which followed the lead of theologians like Augustine, Pseudo-Dionysius, Hugh of St. Victor and Thomas Aquinas. As an example, the author analyzes the 12th century painted ceiling of Zillis in Switzerland whose 153 panels illustrate the importance of number symbolism and the symbolic message which was thought to be hidden in the events of the life of Christ.