And then, in the same way, the success of Alfred and the Saxons soon brought disaster upon them too, in their turn; for, after succeeding in shutting Hastings closely in, and cutting off his supplies of food, they maintained their watch and ward over their imprisoned enemies so closely as to reduce them to extreme distress--a distress and suffering which they thought would end in their complete and absolute submission. Instead of ending thus, however, it aroused them to desperation. Under the influence of the phrensy which such hopeless sufferings produce in characters like theirs, they burst out one day from the place of their confinement, and, after a terrible conflict, which choked up a river which they had to pass with dead bodies and dyed its waters with blood, the great body of the starving desperadoes made their escape, and, in a wild and furious excitement, half a triumph and half a retreat, they went back to the eastern coast of the island, where they found secure places of refuge to receive them. In the course of the subsequent campaigns, a party of the Danes came up the River Thames with a fleet of their vessels, and an account is given by some of the ancient historians of a measure which Alfred resorted to to entrap them, which would seem to be scarcely credible. The account is, that he _altered the course of the river_ by digging new channels for it, so as to leave the vessels all aground, when, of course, they became helpless, and fell an easy prey to the attacks of their enemies. This is, at least, a very improbable statement, for a river like the Thames occupies always the lowest channel of the land through which it passes to the sea. Besides, such a river, in order that it should be possible for vessels to ascend it from the ocean, must have the surface of its water very near the level of the surface of the ocean. There can, therefore, be no place to which such waters could be drawn off, unless into a valley below the level of the sea. All such valleys, whenever they exist in the interior of a country, necessarily get filled with water from brooks and rains, and so become lakes or inland seas. It is probable, therefore, that it was some other operation which Alfred performed to imprison the hostile vessels in the river, more possible in its own nature than the drawing off of the waters of the Thames from their ancient bed.