Up, up they went once more. Up through the tropical forests and among the appalling escarpments of the Sierra. Again they descended the valley slopes, approached the lakes--round which an ominous abandonment prevailed--and crossing the long causeway, entered the Spanish camp. The fault of the insurrection, Cortes learned now, lay with the commander in charge--the foolish and cruel Alvarado, whose barbarous acts on other occasions had needlessly embroiled the Spaniards with the natives. A great celebration and religious festival was being held--Cortes learned--and whilst the Aztec nobles and people were occupied, unsuspecting any hostile act of their guests, Alvarado and the Spaniards, armed to the teeth, had mingled with the crowd with their purpose all planned, fallen upon the unarmed worshippers, and perpetrated a frightful massacre--"without pity or Christian mercy, so that the gutters ran with blood as in a rain-storm," say the chroniclers. The result of this barbarous act was a vengeance and punishment which cost the _Conquistadores_ dear, and stripped them in a few days of all they had won. For the maddened people, roused by sorrow and hate, and urged on by the priests, assailed the Spanish dwelling with frenzied attack. A rain of darts and missiles descended day after day upon the quarters of the Christians, so numerous that they had to be gathered in heaps and burnt in the courtyard. The main point of attack by the Mexicans was the great _teocalli_ of the war-god, which overlooked the Spaniards' quarters, and so fierce was the hail of arrows and stones from this that a sortie was made. Cortes, with Sandoval and Alvarado, and a number of the Spaniards, led a gallant attack on the pyramid, fought their way up its precipitous steps and terraces, and after a frightful hand-to-hand struggle on its giddy summit, forced the Aztecs and their priests over the edge, and rolled the infernal idol of Huitzilopotchli, the war-god, down among the people in the streets below.