But it is time to examine somewhat more closely the circumstances under which St. Paul wrote this epistle and their bearing upon its contents. It was written by him during that imprisonment at Rome[13] the record of which brings to an end the Acts of the Apostles. He can therefore put into his appeals all the force which naturally belongs to one who has sacrificed himself for his principles. 'I, Paul,' he writes, 'the prisoner of Jesus Christ, on behalf of you Gentiles.' He speaks of himself as 'an ambassador in a chain' bound, as he was no doubt, to the soldier which kept him. But the fact that he is a prisoner does not occupy a great place in his mind. In part this is because his imprisonment was not of a highly restrictive character. The Acts conclude by telling us that he was allowed to dwell in his own hired dwelling and to receive all that came to him without let or hindrance to his preaching. And the tone of the 'epistles of the first captivity' is cheerful as to the present and hopeful for the future[14]. But it is more important to notice that {21} the thought of being in prison is apparently swallowed up in St. Paul's imagination by other considerations. For, in the first place, St. Paul was, under whatever restraints, at Rome. He had reached his goal--a new centre of evangelization which was also the centre of the world. Step by step the centre of Christian evangelization had passed toward Rome as its goal. From Jerusalem, which told unmistakably that 'the salvation was of the Jews,' it had moved to Antioch, where in a Greek city Jew met Gentile on equal terms. From Antioch, under St. Paul's leadership, it had passed to Corinth and Ephesus. These were indeed thoroughly Gentile cities, and leading cities of the Empire, but they were provincial. No imperial movement could rest satisfied till it established itself at the centre of the great imperial organization--till it had got to Rome. If we are to understand at all adequately the world in which St. Paul wrote, the thought of the Roman Empire and of the unity which it was giving the world must be clearly before our minds: and it will not be a digression if we pause to dwell upon it at this point when we are considering the significance of St. Paul's situation as at once a prisoner and an evangelist in the great capital. {22} The Roman Empire brought the world, that is the whole of the known world which was thought worth considering, into a great unity of government. What had once been independent kingdoms had now become provinces of the empire, and the whole of the Roman policy was directed towards drawing closer the unity, and educating the provinces in Roman ideas[15].