There are many fragments of this old Roman wall still above ground, and until 1763 a square Roman tower, built of alternate layers of large square stones with bands of red tiles, one of the three that guarded the wall, was still standing in Houndsditch. In 1857 a portion of the Roman wall was discovered near Aldermanbury postern, whilst a portion of a Roman bastion is still to be seen at St Giles’s Church, Cripplegate; another fragment being visible in a street called London Wall Street. There are more Roman remains at the Old Bailey and near George Street, Tower Hill. Fragments are also visible near Falcon Lane, Bush Lane, Scott’s Yard in Cornhill, and in underground warehouses and cellars near the Tower. In the Minories there are yet more remains of this ancient Roman wall. In Thames Street, oaken piles, which were the foundation of the wall, have been discovered. They supported a layer of chalk and stone courses, upon which rested large slabs of sandstone cemented with a mixture of lime, sand, and powdered tiles. The upper part of the wall was coated with flint, and this again was strengthened by rows of tiles. The most interesting of these remains, however, is in the Tower itself—a fragment of the Roman fort or Arx Palatina (the place of strength), which was laid bare some few years ago when some buildings abutting on the White Tower were removed. It is built of the same materials as the fragments of the Roman wall, and shows that William the Conqueror not only erected the most formidable fortress in his newly-conquered country upon the site chosen by the Romans, but that he also incorporated the remains of their handiwork in his building. Whether Alfred the Great restored the Arx Palatina as well as the wall we do not know, but even if the fort were ruined, the fragment now at the base of the White Tower would have shown the Conqueror the value and importance of its defensive position, protecting as it did the eastern end of the city, and guarding the seaward entrance of the Thames. William’s site, however, covered part of the land belonging to the ancient boundary of the Roman occupation, and to provide the necessary space he pulled down a large portion of the Roman wall between the spot where the White Tower now stands and the river front of the fortress.