Wulfstan commenced the new cathedral in the new Anglo-Norman style in 1084, and the monks entered four years later. This, of course, does not imply that the whole cathedral was finished; but only so much of the eastern limb as was sufficient for the daily services; and even this probably not carried higher than the triforium, and provided merely with a temporary roof Many fragments of the lower part of the walls and piers of Wulfstan’s church remain above ground, showing that it was coextensive with the present nave and transepts. [Illustration: NAVE, NORTH SIDE.] Wulfstan’s crypt is almost wholly intact, and enables us to restore the plan of the eastern limb. This consisted of an apse surrounded by an ambulatory, and extended as far as the centre of the present eastern transept. On either side of the choir-aisles apsidal chapels projected eastward from the Norman transept. It is possible that this may explain the curious Norman building on the north side of the choir of Ripon. To simplify the vaulting problem, by making the compartments as small as possible, the crypt was divided into more than a hundred compartments. Owing to the curve of the apse many of the compartments are not square; yet the difficulty of vaulting triangles and trapeziums was successfully overcome, even at this early date. When nearly all the other traditions of Roman methods of construction had been lost, the architects of mediæval Christendom still retained in their crypts the traditions of Roman vaulting. Even the Anglo-Saxon crypt of the village church of Wing has stone vaulting. In the ante-room of the library are preserved the north doors of the cathedral (fourteenth century), under one of the hinges of which are authentic fragments of the skin of some poor wretch flayed alive for sacrilege. The slype, the undercroft of the refectory, and the south-east entrance near it, also belong to Wulfstan’s work. To the early part of the twelfth century belongs the circular chapter-house. Most monastic chapter-houses were constructed in a rectangular form, which best fitted on to the side of a cloister. But the cathedrals of secular canons, when they had chapter-houses, followed the Worcester precedent, except that they were built polygonal instead of circular. Such was the beauty, however, of the new form, that the monastic houses also, in later times, themselves frequently adopted the polygonal form, as at Westminster, Evesham, Belvoir (Benedictine); Margam and Abbey Dore (Cistercian); Alnwick, Cockersand, Thornton, Carlisle, Bridlington, Bolton (Canons Regular). Usually the polygonal chapter-house had a central pier; but it was dispensed with at York and Southwell. The polygonal chapter-house never appears in France; it is one of the most beautiful features in English Gothic.