of his imperial work must be here referred to. By bringing all civilised men under one rule, he prepared them for the worship of one God. This was not without its influence on travel and geographical discovery, for the great barrier between mankind had always been the difference of religion, and Rome, by breaking down the exclusiveness of local religions, and substituting for them a general worship of the majesty of the Emperor, enabled all the inhabitants of this vast empire to feel a certain communion with one another, which ultimately, as we know, took on a religious form.
The Roman Empire will henceforth form the centre from which to regard any additions to geographical knowledge. As we shall see, part of the knowledge acquired by the Romans was lost in the Dark Ages succeeding the break-up of the empire; but for our purposes this may be neglected, and geographical discovery in the succeeding chapters may be roughly taken to be additions and corrections of the knowledge summed up by Claudius Ptolemy.
CHAPTER III.
GEOGRAPHY IN THE DARK AGES.
We have seen how, by a slow process of conquest and expansion, the ancient world got to know a large part of the Eastern Hemisphere, and how this knowledge was summed up in the great work of Claudius Ptolemy. We have now to learn how much of this knowledge was lost or
