Thus Domesday Book gives us a glimpse of a compact little town within a vallum, half a mile from east to west, and a quarter of a mile south to north. We may think of the gravel promontory as covered with houses and their gardens, and inhabited by some thousand souls. A market-place there would have been at or near Carfax, and fairs must have been held there, though we have no mention of them till the reign of Henry I. The "wall" of the enceinte, which, according to Domesday Book, the inhabitants of the mural mansions were compelled to repair, was probably a vallum of earth faced with stone, protected by a deep ditch in front, and surmounted by wood-work to save the soldiers from arrows. D'Oigli, we may presume, put the existing fortifications of the town in order. The fortifications, which were constructed in the reign of Henry III., followed in the main the line of the vallum repaired by D'Oigli. They consisted of a curtain wall and outer ditch, protected by a parapet and by round towers placed at regular intervals and advanced so as to command besiegers who might approach to attack the wall. There were staircases to the top of the towers. A good idea of them and the general scheme of the fortifications may be obtained by a visit to the fragment of the city wall which yet remains within the precincts of New College. The Slype, as it is called, forms a most picturesque approach to New College Gardens, and the old-bastioned wall forms part of the boundary between the New College property and Holywell Street. It is indeed owing to this fact that the wall still remains there intact, for the licence to found a College there was granted to William of Wykeham on condition of keeping the city wall in repair and of allowing access to the mayor and burgesses once in three years to see that this was done, and to defend the wall in time of war. From New College the city wall ran down to the High Street.[5] The East Gate Hotel, facing the new schools, marks the site of the old entrance to the city hereabouts. It is a recent construction in excellent taste by Mr E. P. Warren. From this point the wall ran on to Merton, and thence to Christ Church. The south wall of the Cathedral chapter house is on the line of the old city wall. It is said that some of the old wall was taken down for the erection [Illustration: The Bastion and Ramparts in New College] of the College Hall. Along the north side of Brewer Street (Lambard's Lane, Slaying Lane or King's Street) are here and there stones of the city wall, if not remnants of the walling. At the extreme end of Brewer Street the arch of Slaying Lane Well is just visible, once described as "under the wall." [Illustration: City Walls]