The march of a few miles brought them to an extended wall of solid masonry, built, like the great wall of China, to protect the territory of the Tlascalans from invasion. Though the entrance gate was so constructed that a small army stationed there might have made very powerful resistance, for some reason the Tlascalan force had been withdrawn. The army boldly pressed in, and advanced rapidly, yet using all caution to guard against an ambuscade. They had not proceeded far, however, before they met a large force of the Indians, who attacked them with the utmost fury, and with a degree of military skill and discipline which greatly surprised the Spaniards. Two of the horses were killed, and several of the Spaniards wounded. For a time the situation of the invaders was very precarious; but Cortez soon brought up the artillery, and opened a destructive fire upon the unprotected foe. The thunder of the guns, which the Tlascalans had never heard before, and the horrid carnage of the grape-shot sweeping through their ranks, compelled the warlike natives at last, though slowly and sullenly, to retire. There was, however, no confusion in their retreat. They retired in good order, ever presenting a bold front to their pursuers. Cortez estimated the number of the enemy engaged in this battle at six thousand. The retiring Tlascalans took with them or destroyed all the provisions which the country afforded; but, notwithstanding this, "their dogs," one of the historians of the expedition records, "which we caught when they returned to their habitations at night, afforded us a very good supper." It was now the end of September. The army of Cortez had been gradually increased by recruits from among the natives to three thousand. Immediately after this first battle with the Tlascalans, the whole army was assembled to offer thanks to God for the victory, and to implore his continued protection. The soldiers, with the fresh blood of the Tlascalans hardly washed from their hands, partook of the sacrament of the Lord's Supper according to the rites of the Roman Catholic Church.