In the twelfth century, when the two western towers were constructed, Fulbert’s long galleries were extended and connected with them. The windows were raised and enlarged with the exception of those which were blinded by the porches of the upper church. Four smaller chapels, with pointed windows, were inserted between the large apsidal chapels of Fulbert, and these still exhibit traces of early thirteenth-century painting. At the same period, the transepts being now prolonged, it was found necessary to make two new flights of steps by which they might be entered.
The beautiful doorway of the south staircase dates from this time. Lastly, when the porches of the Cathedral were completed, the transepts were connected therewith by means of vaulted passages, of which the one on the north side is near the Chapel of Notre-Dame-de-Sous-Terre, and the other southern one was turned into the Chapel of S. Nicholas in 1681.
Entering the crypt by the south-eastern door, after noticing the windows of its apsidal chapels, you descend a stone staircase, and by the dim candlelight perceive on your left the long south gallery begun by Fulbert in 1020, and extended in the following century right up to the western tower.
You are now in the original south transept of the crypt, and much of the masonry dates obviously from the tenth century. Turning to the left, the first chapel on the left is now dedicated to S. Martin. It was not originally a chapel, but in the twelfth century was used as an entrance to the crypt. Altered in the seventeenth century, as the windows and vaulting show, it was converted into a chapel in the nineteenth. It contains a few fragments of the original choir screen of the Cathedral destroyed by seventeenth-century vandals.
These fragments, which represent some scenes from the Birth of Our Lord, are very beautiful. Above them, fixed to the wall, are some admirable keystones of the vaulting, and two bas-reliefs with signs of the Zodiac, which still retain some of their original thirteenth-century colouring. Opposite the wooden nineteenth-century _grille_ is a stone from the Church of S. Martin-le-Viandier, which was destroyed during the Revolution. Upon this stone are represented S. Eustace hunting, and on his knees before Christ, who appears to him between the horns of a stag; S. Martin giving his cloak to a poor man; the Virgin and Child between S. Louis and S. John.
