When the road to Jerusalem had been laid fully open, the civil strife, by which the empire had been distracted, had come to an end. Galba, Otho, and Vitellius, one after another, had succeeded to the Imperial sceptre, only to have it snatched from their grasp; and, finally, Vespasian had been advanced to the throne of the Cæsars. Leaving to his son Titus the task of reducing to obedience the rebellious city, Vespasian set sail for Italy; and the Roman army, 60,000 strong,[20] advanced under its new leader to the final encounter in the spring of A.D. 70. Jerusalem was at that time one of the strongest, as well as one of the most picturesque, cities in the world. It stands upon a rocky plateau about 2,600 feet above the level of the sea. On all sides except one it is surrounded by mountains; which do not, however, rise to a much greater altitude than the city itself. The plateau consists of two principal eminences, Zion and Acra, on the former of which stood the Upper City, or the City of David, and on the latter what was called the Lower City. A third—a smaller and somewhat lower hill, called Moriah—was anciently divided from Mount Acra by the Tyropœon, or Valley of the Cheesemongers, which was filled up by the Maccabees, who raised Moriah to the same level as the neighbouring hill. It was on the summit of Moriah that the Temple stood. In later times the suburb called Bezetha was added to the city, and the whole environed by walls. Of these there were three—one inside another. The first began on the north side at the tower called Hippicus, terminating at the western cloister of the Temple. The second wall began at the gate called Gennath, enclosing the northern quarter of the city only, and ending at the Tower of Antonia. The third, which was designed to protect Bezetha, was incomplete at the time of the outbreak of the Jewish war, but was then completed, in anticipation of the approaching siege. These walls were strengthened by towers of solid masonry—some of the stones being of enormous size—and rose to a great height above the level of the walls. The Tower of Antonia stood on a rock ninety feet high, the fortress itself being fully seventy feet higher; and at the portions not defended by these walls, the platform of rock itself, sinking down, as it did almost with a sheer descent, into the ravines below, formed an impregnable defence. In times when the use of gunpowder was unknown, it could be captured only by blockade, or after the most frightful waste of human life.