The Pool of the Thames was crowded, and as the wind freshened the ships looked even more like huge white-winged birds. Around them sailed and wheeled and fluttered the real sea-birds, picking up their living from the scraps thrown overboard,--swans, gulls, wild geese and ducks, here and there a strange bird lured to the harbor by hope of spoil. The oddly mated companions, the man and the boy, walked along busy Thames Street and came to Tower Hill and the great gray fortress-towers, with a double line of wall coiled around the base, just outside the City of London. The deep wide moat fed from the river made an island for the group of buildings with the square White Tower in the middle. "None of your friends live there, I suppose?" the young man inquired, and Nicholas smiled rather dubiously, for he was not certain whether it was a joke or not. The Tower had been prison, palace and fort by turns, but common criminals were not imprisoned there--only those who had been accused of crimes against the State. "Lucky you," the youth added. "London is much pleasanter as a residence, I assure you. I lodged not far from here when I first came, but now I lodge----" That sentence was never finished. Clattering down Tower Hill came a troop of horse, and one, swerving suddenly, caught Nicholas between his heels and the wall, and by the time the rider had his animal under control the little fellow was lying senseless in the arms of the stranger, who had dived in among the flying hoofs and dragged him clear. The rider, lagging behind the rest, looked hard at the two, and then spurred on without even stopping to ask whether he had hurt the boy. Before Nicholas had fairly come to himself he shut his teeth hard to keep from crying out with the pain in his side and left leg. The young man had laid him carefully down close by the wall, and just as he was looking about for help three of the troopers came spurring back, dismounted, and pressed close around the youth as one of them said something in French. He straightened up and looked at them, and in spite of his pain Nicholas could not help noticing that he looked proudly and straightforwardly, as if he were a gentleman born. He answered them in the same language; they shook their heads and made gruff, short answers. The young man laid his hand on his dagger, hesitated, and turned back to Nicholas. "Little lad," he said, "this is indeed bad fortune. They will not let me take you home, but----" So deftly that the action was hidden from the men who stood by, he closed Nicholas' hand over a small packet, while apparently he was only searching for a coin in his pouch and beckoning to a respectable-looking market-woman who halted near by just then. He added in a quick low tone without looking at the boy, "Keep it for me and say nothing."