With the death of Sulla ends what we may call the first act of the Roman Revolution. We are now in the middle of a revolution in more than one sense of that word. The constitution and the government of Rome are being slowly but surely changed, and at the same time the era of the free and independent city-state of the Græco-Roman world is being brought to an end. Both these changes, as we can see now, were inevitable; without them the civilised world could not have been defended against barbarian invasion, or Italy united into a contented whole possessed of Roman citizenship. In the first act, as I have called it, the immediate danger of invasion was checked, both in north and east, and Italy had become Roman, enjoying perfect equality with Rome under the great body of Roman law now being rapidly developed. But, in truth, this inevitable work of change was not as yet half done. It was soon found that both in north and east some definite system of frontier must be fixed, or the Empire would be in continual peril from without. It was also found that Sulla’s constitution would not work, and that to defend the frontiers of civilisation effectively there must be a government of sterner force, whatever form that force might take. Thus in the second act of the Revolution we have two main points to attend to: first, the settlement of the frontiers against Oriental despots and wandering hordes of Germans: secondly, the acquisition of power by a great soldier-statesman, Julius Cæsar, and the abandonment, as a working power, of the ancient polity of Senate and people. And inasmuch as this period of revolution was also the age of the best and purest bloom of Latin literature, I must find space for a few words about Cicero, Lucretius, and Catullus. I said in the last chapter that there was a very dangerous enemy threatening the eastern or Greek part of the Empire. This was Mithradates, king of Pontus, that part of Asia Minor which borders on the Euxine (Black Sea) eastwards: a man of genius and ambition, and by no means to be reckoned a barbarian. It is curious that he began his great career by protecting Greek cities against their enemies, and one is tempted to ask whether he might not have been at least as beneficent a champion and master for the Greek world as Rome herself. But we must look at things with Roman eyes if we are to understand the work of Rome in the world; we must think of Mithradates as the Romans then did, as the deadly enemy alike of Greek freedom and of Roman interests.