As they advanced into a country of rougher and bolder features, their progress was suddenly arrested by a remarkable fortification. It was a stone wall nine feet in height, and twenty in thickness, with a parapet, a foot and a half broad, raised on the summit for the protection of those who defended it. It had only one opening, in the centre, made by two semicircular lines of wall overlapping each other for the space of forty paces, and affording a passage-way between, ten paces wide, so contrived, therefore, as to be perfectly commanded by the inner wall. This fortification, which extended more than two leagues, rested at either end on the bold natural buttresses formed by the sierra. The work was built of immense blocks of stones nicely laid together without cement;[100] and the remains still existing, among which are rocks of the whole breadth of the rampart, fully attest its solidity and size.[101] This singular structure marked the limits of Tlascala, and was intended, as the natives told the Spaniards, as a barrier against the Mexican invasions. The army paused, filled with amazement at the contemplation of this Cyclopean monument, which naturally suggested reflections on the strength and resources of the people who had raised it. It caused them, too, some painful solicitude as to the probable result of their mission to Tlascala, and their own consequent reception there. But they were too sanguine to allow such uncomfortable surmises long to dwell in their minds. Cortés put himself at the head of his cavalry, and, calling out, “Forward, soldiers, the Holy Cross is our banner, and under that we shall conquer,” led his little army through the undefended passage, and in a few moments they trod the soil of the free republic of Tlascala.[102] CHAPTER II REPUBLIC OF TLASCALA--ITS INSTITUTIONS--EARLY HISTORY--DISCUSSIONS IN THE SENATE--DESPERATE BATTLES 1519 Before advancing further with the Spaniards into the territory of Tlascala, it will be well to notice some traits in the character and institutions of the nation, in many respects the most remarkable in Anahuac. The Tlascalans belonged to the same great family with the Aztecs.[103]{*} They came on the grand plateau about the same time with the kindred races, at the close of the twelfth century, and planted themselves on the western borders of the lake of Tezcuco. Here they remained many years, engaged in the usual pursuits of a bold and partially civilized people.