One night the earl quitted his castle with an escort of only thirty horsemen. The object with which he did so is variously stated; but the most probable account is that he was betrayed by some followers of Rufus, who offered to give up the town of Newcastle into his possession. The earl was surprised by a body of Norman troops, and while many of his retinue were cut to pieces, he escaped from his assailants, and took sanctuary at St. Oswin's monastery, Tynemouth. By the laws of chivalry, the blackest criminal was safe under the shadow of the Cross; but the soldiers of William were deterred neither by those laws, nor by any respect for the sacredness of the place. They pursued the earl to his sanctuary, and after a desperate resistance made him prisoner. Having carried Earl Mowbray to Bamborough, and placed him before the gates of his castle, they demanded a parley with the Countess Matilda. On her appearance, they exhibited her husband as a prisoner, and told her that they would put out his eyes before her face unless she at once gave up the castle into their hands. Matilda is described as having been remarkable for her beauty; she was young, and had been married to the earl only a few months before. She did not long hesitate, but ordered the gates to be thrown open. Among the followers of Mowbray was one through whom Rufus gained a knowledge of the extent of the conspiracy, and of the persons implicated in it. The subsequent fate of Mowbray was that of a living death. His young wife had indeed saved him from blindness, but he was not the less deprived of the light of day. Condemned to perpetual imprisonment, he was confined in a dungeon at Windsor Castle, where we read that he dragged on existence for thirty years afterwards. Another account, however, has it that he ended his life as a monk. The property of the banished nobles was plundered by the adherents of the king, and then left for some time uncultivated, and without owners. Nevertheless, the people of the town or hundred in which such estates lay, were compelled to pay the full amount of land tax as before. The king, also, forcibly raised troops of men to build a wall encircling the Conqueror's Tower at London, a bridge over the Thames, and, near the West Minster, a hall or palace of audiences, for the stated assemblies or assizes of the great barons.[11]