ll Cathars accepted the New Testament as divinely inspired, and some of them also admitted the Wisdom Books and the Prophetical Books of the Old Testament to their scriptural canon; but (except for the school of John of Lugio) they all rejected the Pentateuch and the Historical Books. This created a two-fold problem for them. First, the writers of the Biblical books which they did accept regarded the Pentateuch and the Historical Books of the Old Testament as divinely inspired and frequently cited them as authoritative. Secondly, the Cathars lived in a society which considered that the Pentateuch and the Historical Books of the Old Testament were the most accurate factual record of human history. In this paper I have tried to explore how the Cathars responded to those challenges.