Since, owing to an almost incredible act of royal vindictiveness in A.D. 1538, Becket's glorious shrine belongs only to the history of the past, some account of its splendours will not be out of place in this part of our account of the cathedral. It stood on the site of the ancient chapel of the Trinity, which was burnt down along with Conrad's choir in the destructive fire of A.D. 1174. It was in this chapel that Thomas à Becket had first solemnized mass after becoming archbishop. For this reason, as we may fairly suppose, this position was chosen to enshrine the martyr's bones, after the rebuilding of the injured portion of the fabric. Though the shrine itself has been ruthlessly destroyed, a mosaic pavement, similar to that which may be seen round the tomb of Edward the Confessor in Westminster Abbey, marks the exact spot on which it stood. The mosaic is of the kind with which the floors of the Roman basilicas were generally adorned, and contains signs of the zodiacs and emblems of virtues and vices. This pavement was directly in front of the west side of the shrine. On each side of the site is a deep mark in the pavement running towards the east. This indentation was certainly worn in the soft, pinkish marble by the knees of generations of pilgrims, who prostrated themselves here while the treasures were displayed to their gaze. In the roof above there is fixed a crescent carved out of some foreign wood, which has proved deeply puzzling to antiquaries. A suggestion, which hardly seems very plausible, connects this mysterious crescent with the fact that Becket was closely related, as patron, with the Hospital of St. John at Acre. It was believed that his prayers had once repulsed the Saracens from the walls of the fortress, and he received the title of St. Thomas Acrensis. Near this crescent a number of iron staples were to be seen at one time, and it is likely that a trophy of some sort depended from them. The Watching Tower was set high upon the Tower of St. Anselm, on the south side of the shrine. It contained a fireplace, so that the watchman might keep himself warm during the winter nights, and from a gallery between the pillars he commanded a view of the sacred spot and its treasures. A troop of fierce ban-dogs shared the task of guarding the shrine from theft. How necessary such precautions were is shown by the fact that such a spot had to be guarded not only from common robbers in search of rich booty, but also from holy men, who were quite unscrupulous in their desire to possess themselves and their own churches of sacred relics. Within the first six years after Becket's death we read of two striking instances of the lengths to which distinguished churchmen were carried by what Dean Stanley calls "the first frenzy of desire for the relics of St. Thomas." Benedict, a monk of Christ Church, and "probably the most distinguished of his body," was created Abbot of Peterburgh in A.D. 1176. Disappointed to find that his cathedral was very poor in the matter of relics he returned to Canterbury, "took away with him the flagstones immediately surrounding the sacred spot, with which he formed two altars in the conventual church of his new appointment, besides two vases of blood and parts of Becket's clothing." Still more striking and characteristic of the prevalent passion for relics is the story of Roger, who was keeper of the "Altars of the Martyrdom," or "Custos Martyrii." The brothers of St. Augustine's Abbey were so eager to obtain a share in the glory which their great rival, the neighbouring cathedral, had won from the circumstances of Becket's martyrdom within its walls, that they actually offered Roger no less a reward than the position of abbot in their own institution, on condition that he should purloin for them some part of the remains of the martyr's skull. And not only did Roger, though he had been specially selected from amongst the monks of Christ Church to watch over this very treasure, agree to their conditions, and after duly carrying out this piece of sacrilegious burglary become Abbot of St. Augustine's; but the chroniclers of the abbey were not ashamed to boast of this transaction as an instance of cleverness and well-applied zeal.