Then follow new strata, the Christian age, the Middle Ages, and modern times, with their innumerable churches, monasteries, and massive solemn palaces. Christianity built on the ruins of paganism. Ancient and modern times are inextricably mixed. Up there on the Capitoline hill rides a Roman Emperor, Marcus Aurelius, in bronze. Look round, and there on the farther bank of the Tiber another horseman looks over the eternal city, the brave champion of young Italy's liberty, Garibaldi. You ride through a street lined with grand shops in new buildings, and in a couple of minutes you are at the Forum Romanum, the Roman market-place, the heart of the world empire, the square for markets, popular assemblies, and judicial courts, a marble hall in the open air. Over its flags, victors, accompanied by their comrades in arms and their prisoners, marched up to the Capitol to sacrifice in the temple of Jupiter, where now only a few pillars and ruins remain of all the splendour Julius Caesar and Augustus lavished upon it. At one time we are like pilgrims in the fine Church of St. Peter; at another we are strolling under the triumphal arch of Titus, erected in remembrance of the destruction of Jerusalem in the year A.D. 70. The largest and grandest ruin in Rome is the Colosseum (Plate XXVI.), an amphitheatre which was built by the two Emperors, Vespasian and Titus, and which was finished eighty years after the birth of Christ. The outside walls are nearly 160 feet high. The tiers of benches, which could accommodate 85,000 spectators, were divided into four blocks, of which the outermost and highest was set apart for freedmen and slaves with their women. The tickets were of ivory, and indicated the different places so clearly that every one could easily find his way in the huge passages, colonnades, and staircases. The benches were covered with marble, and many statues of the same material adorned the upper walls of the amphitheatre. The spectacles were usually held in the daytime, and to abate the heat of the sun immense silken awnings were stretched over the arena and the auditorium. When the theatre was full, it presented a scene of dazzling splendour. In the best places sat senators in purple-bordered togas, the priests of the various temples, the Vestal virgins in black veils, warriors in gold-embroidered uniforms. There sat Roman citizens in white or coloured togas, bareheaded, beardless, and closely cropped, eagerly talking in a language as euphonious as French and Italian. All strangers who were staying in Rome were there, ambassadors from all the known countries of the world, statesmen, merchants, and travellers from Germany and Gaul, from Syria, Greece, and Egypt.