The year 461 saw the great organisation which had ruled and united Europe for so long trembling into decay. The history of the Empire in relation to Christianity is indeed a remarkable one. The imperial religion had been the necessary and deadly foe of the religion of Jesus Christ; it had fought and had been conquered. Gradually the Empire itself with all its institutions and laws had been transformed, at least outwardly, into a Christian power. Questions of Christian theology had become questions of imperial politics. A Roman of the second century would have wondered indeed at the transformation which had come over the world he knew: it seemed as if the kingdoms of the earth had become the kingdoms of the Lord and of His Christ. But also it seemed that the new wine had burst the old bottles. The boundaries of the Roman world had been outstepped: nations had come in from the East and from the West. The {2} system which had been supreme was not elastic: the new ideas, Christian and barbarian alike, pressed upon it till it gave way and collapsed. And so it came about that if Christianity had conquered the old world, it had still to conquer the new. [Sidenote: The decaying Empire.] Now before the Church in the fifth century there were set several powers, interests, duties, with which she was called upon to deal; and her dealing with them was the work of the next five centuries. They were,--the Empire, Christian, but obsolescent; the new nations, still heathen, which were struggling for territory within the bounds of the Empire, and for sway over the imperial institutions; the distant tribes untouched by the message of Christ; and the growth, within the Church itself, of new and great organisations, which were destined in great measure to guide and direct her work. Politics, theology, organisation, missions, had all their share in the work of the Church from 461 to 1003. In each we shall find her influence: to harmonise them we must find a principle which runs through her relation to them all. [Sidenote: The need of unity.]