When the Danes at Ely, on whose powerful aid Hereward had built such hopes, received orders to return home, they were far from manifesting any reluctance. They seemed determined, however, not to go empty-handed. In fact, the temptation of carrying off the ornaments and sacred vessels which Hereward had brought from the abbey of Peterborough was more than the grisly Northmen could resist; and seizing everything in the way of treasure upon which they could lay hands, they embarked, and turning the prows of their ships homewards, gave their sails to the wind, laughing grimly at the ridiculous plight in which they left the men they had come to save. Affairs now hurried to a catastrophe. Ivo Taille-Bois and Abbot Turauld rejoiced in the hope of triumph and revenge; and Hereward could not but confess that the prospects of the Saxons at Ely were dismal in the extreme. By-and-by news reached the Camp of Refuge that William was assembling forces, and that a great blow was to be struck, and as weeks passed on, the Camp of Refuge was invested by land and water. On every side workmen were set to form dykes and causeways over the marshes; and on the west, over waters covered with reeds and willows, the Normans commenced the construction of a road three hundred paces in length. But most of the labour was found to be in vain. The Normans had no rest. Hereward and his friends, incessant in their attacks and artful in their stratagems, constantly interrupted the work; and the workmen, finding themselves disturbed in the most sudden and unexpected manner, gave way to superstitious terror. "Assuredly," they exclaimed, "this Hereward is in league with the Evil One." "Think you so?" cried Ivo Taille-Bois; "then we must fight him with his own weapons." The idea of the Angevin viscount was highly approved of; and he soon procured the services of a witch, whose enchantments, he declared, would disenchant Hereward's operations. Accordingly this woman was brought to the scene of action, and posted in a wooden tower at the place where the work was in progress. The result, however, was not such as Ivo had predicted. In fact, while the Norman pioneers and soldiers were all confident in the potency of the witch's charms, Hereward suddenly made a sally, set fire to the osiers that covered the marsh like a forest, and gave witch, workmen, and warriors to the flames. At this fresh misfortune the Normans began to consider their enterprise hopeless, and the blood of Ivo Taille-Bois boiled at the thought of being baffled by a "degenerate burgess" like Hereward. The address and activity of the Saxon chief really seemed to preclude the possibility of success. Nevertheless, the Normans persevered; and for months the Isle of Ely was blockaded so closely that provisions were with extreme difficulty obtained from without.