The main object to which the reigning classes gave their attention was war,--the extension of the empire. "_Ubi castra, ibi respublica_." Republican Rome was a camp, controlled by aristocratic generals. Dominion and conquest were their great ideas, their aim, their ambition. To these were sacrificed pleasure, gain, ease, luxury, learning, and art. And when they had conquered they sought to rule, and they knew how to rule. Aside from conquest and government there is nothing peculiarly impressive in Roman history, except the struggles of political leaders and the war of classes. But in these there is wonderful fascination. The mythic period under kings; the contests with Latins, Etruscans, Volscians, Samnites, and Gauls; the legends of Porsenna, of Cincinnatus, of Coriolanus, of Virginia; the heroism of Camillus, of Fabius, of Decius, of Scipio; the great struggle with Pyrrhus and Hannibal; the wars with Carthage, Macedonia, and Asia Minor; the rivalries between patrician and plebeian families; the rise of tribunes; the Maenian, Hortensian, and Agrarian laws; the noble efforts of the Gracchi; the censorship of Cato; the civil wars of Marius and Sulla, and their exploits, followed by the still greater conquests of Pompey and Julius; these, and other feats of heroism and strength, are full of interest which can never be exhausted. We ponder on them in youth; we return to them in old age. And yet the real grandeur of Rome is associated with the emperors. With their accession there is a change in the policy of the state from war to peace. There is a greater desire to preserve than extend the limits of the empire. The passion for war is succeeded by a passion for government and laws. Labor and toil give place to leisure and enjoyment. Great works of art appear, and these become historical,--the Pantheon, the Forum Augusti, the Flavian Amphitheatre, the Column of Trajan, the Baths of Caracalla, the Aqua Claudia, the golden house of Nero, the Mausoleum of Hadrian, the Temple of Venus and Rome, the Arch of Septimus Severus. The city is changed from brick to marble, and palaces and theatres and temples become colossal. Painting and sculpture ornament every part of the city. There are more marble busts than living men. Life becomes more complicated and factitious. Enormous fortunes are accumulated. A liberal patronage is extended to artists. Literature declines, but great masterpieces of genius are still produced. Medicine, law, and science flourish. A beautiful suburban life is seen on all the hills, while gardens and villas are the object of perpetual panegyric. From all corners of the earth strangers flock to see the wonders of the mighty metropolis, more crowded than London, more magnificent than Paris, more luxurious than New York. Fetes, shows, processions, gladiatorial combats, chariot races, form the amusement of the vast populace. A majestic centralized power controls all kingdoms, and races, and peoples.