On the appointed morning, the two armies, after the usual celebration of mass, advanced along their respective causeways against the city.[43] They were supported, in addition to the brigantines, by a numerous fleet of Indian boats, which were to force a passage up the canals, and by a countless multitude of allies, whose very numbers served in the end to embarrass their operations. After clearing the suburbs, three avenues presented themselves, which all terminated in the square of Tlatelolco. The principal one, being of much greater width than the other two, might rather be called a causeway than a street, since it was flanked by deep canals on either side. Cortés divided his force into three bodies. One of them he placed under Alderete, with orders to occupy the principal street. A second he gave in charge to Andres de Tápia and Jorge de Alvarado; the former a cavalier of courage and capacity, the latter a younger brother of Don Pedro, and possessed of the intrepid spirit which belonged to that chivalrous family. These were to penetrate by one of the parallel streets, while the general himself, at the head of the third division, was to occupy the other. A small body of cavalry, with two or three field-pieces, was stationed as a reserve in front of the great street of Tacuba, which was designated as the rallying-point for the different divisions.[44] Cortés gave the most positive instructions to his captains not to advance a step without securing the means of retreat by carefully filling up the ditches and the openings in the causeway. The neglect of this precaution by Alvarado, in an assault which he had made on the city but a few days before, had been attended with such serious consequences to his army that Cortés rode over, himself, to his officer’s quarters, for the purpose of publicly reprimanding him for his disobedience of orders. On his arrival at the camp, however, he found that his offending captain had conducted the affair with so much gallantry, that the intended reprimand--though well deserved--subsided into a mild rebuke.[45]