At the close of summer, Alfred considered it necessary to be in the neighbourhood of the metropolis, to protect his subjects from the attacks of the Danes while they gathered in their harvest. Driving in foragers, attacking outposts, and checking attempted sallies, had rendered Alfred as familiar with the construction of the invaders' fortresses as they were themselves; and one day while meditating how he could most advantageously strike a decisive blow, and compel the enemy to abandon their stronghold, he hit upon the daring plan of draining the river Lea, and leaving the whole of the Danish fleet aground. To accomplish this, he ordered his soldiers to dig three new channels below the level of the river, and to raise two fortresses on either side the Lea to protect their operations. He drew off the waters into a tributary stream which emptied itself into the Thames, so that, as an old writer says, "where a ship might sail in time afore past, then a little boat might scarcely row." In the night, Hastings again broke through the toils with which the inventive genius of Alfred had encompassed him; and abandoning his ships, which were now useless, he contrived to send off the wives and children of his followers into East Anglia, to the care of his countrymen; he thus escaped from Alfred, and reached Bridgenorth, near the Severn, where he again intrenched himself. Although, as usual, he was quickly followed by the Saxon king, yet so strong was the military position which the Danes occupied, that with the exception of a slight skirmish or two, they were allowed to pass the winter unmolested. Many of the Danish vessels which Hastings had left behind were again set afloat, and conducted with great triumph into the Thames. The remainder were burnt and destroyed.