Le Mystere des Cathedrals - Extract

The ground plan of a Christian building reveals its preparation by the sign of the cross, which points to the first stone upon which Jesus built his church. And the Medieval Freemasons have symbolically followed the divine example. But before this hewn stone is dressed, the rough, impure, gross and unpolished stone was often given the image of the devil.

Notre Dame of Paris possessed a similar hieroglyph, situated under the rood screen, at the corner of the choir rail. It was a figure of the devil, opening an enormous mouth in which the faithful extinguish their candles. That’s the sculpture block of stone which was marked with streaks of candle grease and blackened with smoke. The common people called the image Master Peter of the corner. Now this stone, which is intended to represent the first matter of the work, personified under the aspect of Lucifer (the star) which was the symbol of our cornerstone, the headstone of the corner - the stone which the builders rejected which has been made the headstone of the corner, on which rests the whole structure of the building. 

The churches of Sens, Rheims, Auxerre, St Quentin, Poitiers and Bayeux preserved their labyrinths. And Amiens and Chartres.