Conquest did not involve in ancient times any responsibility towards the conquered; war was believed to be, and was, a profitable investment; as Rome pushed her conquests, the organization which she gave to the conquered peoples was one which suited her own purposes, she did not consult their convenience, external pressure alone forced her to modify the conditions of conquest which were universally accepted by the ancient world; very gradually and very reluctantly she broke down the barriers which surrounded the city state of antiquity, and admitted first her immediate neighbours, and lastly the whole of Italy to some sort of constitutional communion with her. For a long time war had been forced upon Rome, the invasions of the Gauls, the domination of Carthage in the Mediterranean, the invasion of Pyrrhus, the invasion of Hannibal, and lastly the invasion of the Cimbrians and Teutons involved her in a succession of defensive wars; the city itself could not find a sufficient supply of soldiers, and the price which Rome had to pay for being allowed to recruit over Italy was the partial incorporation of the Italians in the State. Wars of defence were accompanied and followed by wars of aggression; success encouraged speculation; after the happy issue of the second war with Carthage the Roman oligarchy began seriously to turn its attention to the Eastern Mediterranean, and another century found it entering upon the heritage of Alexander. This is the turning point of Roman history; from this time onwards a new conception occupied the minds of ambitious Romans; alongside of the ideal of the city State there existed the ideal of an extended Empire, of a world-wide organization, of something more permanent than conquest; alongside of the men who dreamed of Platonic republics in which perfect justice would be realized, there grew up men who formed a yet grander and no less civilized ambition. Pompey triumphed over Mithridates wearing a robe which had been worn by Alexander; Augustus used a head of Alexander for his signet ring; it was by the example of Alexander that Cleopatra seduced Mark Antony. Alexander was no vulgar adventurer; he solved a problem which had hitherto baffled the most highly civilized race of the ancient world; he combined the city state of the Greeks with the Imperial organization of the Persians; and though, when the Romans came into close contact with Alexander’s Empire it had fallen into fragments, each fragment preserved the impress of the great whole, and Roman generals could converse at Pergamus, at Antioch, or at Alexandria, with men trained to administer states in terms of the wider conceptions derived from Alexander and possibly through him from Aristotle; at the same time many men accustomed to deal with financial problems on a large scale passed into the service of the Roman conquerors as slaves or honoured dependants.