Let us glance, for example, at his attitude towards slavery, which, when we last noticed it, was threatening to become a deadly poison in the Roman system. During the first century of the Empire, chiefly under the influence of the Stoic philosophy, as later on under that of Christianity, there had been growing up a feeling that a slave was, after all, a human being, and had some claim to be treated as such under the Roman law, beneficent in its dealings with all other human beings. Antoninus followed out this new idea both in legislation and in his private life, as did his successor also, who adored his memory. They limited the right of a master over his slaves in several ways; ordaining that if cruelty were proved against a master, he should be compelled to sell the slave he had ill-treated. It is noteworthy, too, that the philosopher in whom they most delighted, Epictetus, had himself originally been a slave. There is no better way of realising the spirit of humanity which actuated Antoninus and his successor than by making some acquaintance with the moral philosophy of Epictetus, and the _Meditations_ of Marcus Aurelius. The _Golden Sayings of Epictetus_, in the Golden Treasury Series,[18] and Dr. Rendall’s translation of the _Meditations_, will be of use to those who do not read Greek. Hadrian had left the Empire well guarded, and it does not seem to have occurred to Antoninus to see for himself that Hadrian’s vigilance was maintained. This was the one weak point of his reign, and it cost his successors dear. He only once left Italy, and his mind was never occupied with wars or rumours of wars; he lived tranquilly, and died peacefully, without trouble or anxiety. But we know that even before his death clouds were beginning to gather on the northern frontier; and we cannot but feel that the beautiful tranquillity of Antoninus’s life was hardly compatible with the duty of an imperial guardian. Marcus Aurelius, the author of the _Meditations_, succeeded his uncle and adoptive father in A.D. 161. Though not the greatest of the four as a ruler, he was the most remarkable as a man, and holds a higher place than the others in the world’s esteem. We may find parallels in history to Trajan, less easily, perhaps, to Hadrian and Antoninus; but there is no monarch like Marcus, not even in the history of the Jews. It is, indeed, astonishing that Rome, Rome of the hard practical temperament, should have produced a ruler who was a philosopher and almost a saint, and yet capable of government. It is the last striking manifestation of the old Roman spirit of duty and discipline, now kindled into a real ethical emotion by the teaching of the Stoics, far the most inspiring creed then available for a man of action. Without any aid from Christianity, which, indeed, he could not understand and occasionally persecuted, Marcus learnt not only how to make his own life pure, but how to live and work for the world of his day.