This monster in human guise Basil had acquired from a certain nobleman in the suite of the Byzantine ambassador extraordinary to the Holy See. Basil looked up at the moon which just then emerged from the shadow of a cloud. Then he gave a nod of satisfaction. "Your promptness argues well for your success," he turned to his runner who was cowering at his feet, the ashen face with the blinking and inflamed eyes raised to his master. "Know you the road to southward, my good Daoud?" The Moor gave a nod and Basil proceeded. "You must depart this very night. Take the road that leads by Benevento to the Shrines of the Archangel. You will overtake the Senator and deliver into his hands this token. You will return forthwith and bring to me--his answer. Do I make myself quite clear to your understanding, my good Daoud?" The Moor fell prostrate and touched Basil's buskin with his forehead. "Up!" the latter spurned the kneeling brute. "To-morrow night must find you in the Witches' City." With these words he placed into the Moor's hand a small article, carefully tied and sealed. The twain exchanged a mute glance of mutual understanding, then Daoud gave a bound, darted forward and shot away like an arrow from the bow. Almost instantly he was out of sight. The hound bounded after him but, obedient to his master's call, instantly returned to the latter's feet. For some time Basil remained near the rock where the weird ceremony had taken place. "The Rubicon is passed," he muttered. "The stars--or the abyss." Then, slowly quitting the stupendous ruins of the Amphitheatre, he took the direction of the Catacombs of St. Calixtus. CHAPTER VII THE FACE IN THE PANEL On the following day Tristan entered upon his duties as captain of the Senator's guard. The first person upon whom he chanced on his rounds at the Lateran was the Grand Chamberlain, who inquired affably how his penitences were progressing and expressed the hope that he had received final absolution, and that his sins would not weigh too heavily upon his soul. Basil commended him for his zeal in the cause of the Senator, hinting incidentally that his duties between the Lateran and Castel San Angelo need not deprive him of the society of the fair Roman ladies, who would welcome the stranger from Provence and would doubtlessly enmesh his heart, if it were not well guarded. He then proceeded to caution Tristan with respect to his exalted prisoner. Numerous attempts at abduction had been made from time to time, Tristan having, by his prowess and daring, prevented the last, emanating doubtlessly from the Pontiff's nearest kith and kin. The men under him could be fully relied upon. Nevertheless, it behooved him to be circumspect. After a time Basil departed, and Tristan went about his business, inspecting the guard and familiarizing himself with the place where he was to keep his first watch.