It may appear extraordinary that Guatemozin should have been able to provide for the maintenance of the crowded population now gathered in the metropolis, especially as the avenues were all in the possession of the besieging army.[34] But, independently of the preparations made with this view before the siege, and of the loathsome sustenance daily furnished by the victims for sacrifice, supplies were constantly obtained from the surrounding country across the lake. This was so conducted, for a time, as in a great measure to escape observation; and even when the brigantines were commanded to cruise day and night, and sweep the waters of the boats employed in this service, many still contrived, under cover of the darkness, to elude the vigilance of the cruisers, and brought their cargoes into port. It was not till the great towns in the neighborhood cast off their allegiance that the supply began to fail, from the failure of its sources. This defection was more frequent, as the inhabitants became convinced that the government, incompetent to its own defence, must be still more so to theirs; and the Aztec metropolis saw its great vassals fall off one after another, as the tree over which decay is stealing parts with its leaves at the first blast of the tempest.[35] The cities which now claimed the Spanish general’s protection supplied the camp with an incredible number of warriors; a number which, if we admit Cortés’ own estimate, one hundred and fifty thousand,[36] could have only served to embarrass his operations on the long extended causeways. Yet it is true that the Valley, teeming with towns and villages, swarmed with a population--and one, too, in which every man was a warrior--greatly exceeding that of the present day. These levies were distributed among the three garrisons at the terminations of the causeways; and many found active employment in foraging the country for provisions, and yet more in carrying on hostilities against the places still unfriendly to the Spaniards. Cortés found further occupation for them in the construction of barracks for his troops, who suffered greatly from exposure to the incessant rains of the season, which were observed to fall more heavily by night than by day. Quantities of stone and timber were obtained from the buildings that had been demolished in the city. They were transported in the brigantines to the causeway, and from these materials a row of huts or barracks was constructed, extending on either side of the works of Xoloc. It may give some idea of the great breadth of the causeway at this place, one of the deepest parts of the lake, to add that, although the barracks were erected in parallel lines on the opposite sides of it, there still remained space enough for the army to defile between.[37]