The Norman work of this period is the earliest of which any traces remain in the present church, unless the doubtful signs on a shaft in the exterior are to be taken as evidence of Saxon workmanship. This shaft is attached to the north wall of the Chapel of St. John-the-Divine (now used as a clergy vestry), which is perhaps the oldest part of the fabric. The undoubted Norman remains consist of three arches in the same chapel, where their outline is just discernible among the brickwork; the fragment of a string-course, with billet moulding, on the inner wall of the north transept; a portion of the Prior's entrance to the cloisters; the old Canons' doorway; and an arcaded recess. Of these, it may be briefly remarked that the remains of the Prior's door, showing the mutilated shafts and the zigzag moulding of the jambs, are preserved, _in situ_, in the outer face of the north wall to the new nave. The outline of the Canons' entrance, obviously of much simpler moulding, will be seen on the inner side of the same wall, towards the west end. The Norman recess lies still farther to the west on the same side. Quite recently a valuable relic of the same period has been discovered in the north-east corner within the above-mentioned chapel (by the side of the new Harvard window)--apparently part of the original arcading to the apse. Early in the thirteenth century London was visited by one of those great fires, which occurred at rather frequent intervals, before the greatest of all, in 1666, led to the rebuilding of the city, and better means for its protection. The date of the particular fire is sometimes given as 1207, sometimes as 1212 or 1213. It is not unlikely that there were several, in one or other of which London Bridge, Southwark, and the church were seriously injured. (_Vide_ Stow and Harleian MSS., No. 565.) The repairs were soon taken in hand by Peter de la Roche, otherwise de Rupibus, Bishop of Winchester (1205-1238), who altered the nave into the Early English, which was then generally superseding the heavier Norman work, and shortly afterwards built the choir and retro-choir in a still lighter and more ornate style. The architecture gives us the approximate date of de la Roche's work as the early part of the thirteenth century, which is about as near as we can get to it in the absence of a more precise record than that it was "begun after the fire." In consequence of this, or some previous fire, the Canons were led to found a hospital close to the Priory for the relief of the distress and disease caused by the disaster. During the restorations by Peter de Rupibus, in or about 1228, he had the hospital transferred to a more favourable site in the neighbourhood, where the air was fresher and water more abundant, and dedicated it to St. Thomas of Canterbury, to whom the chapel on London Bridge was also dedicated.[4]