with his northerly
conquests. One result 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 perverted--how geography, for a time, lost the character of
a science, and became once more the subject of mythical fancies
similar to those which we found in its earliest stages. Instead of
knowledge which, if not quite exact, was at any rate approximately
measured, the mediaeval teachers who concerned themselves with the
configuration of the inhabited world substituted their own ideas
of what ought to be.[1] This is a process which applies not alone
to geography, but to all branches of knowledge, which, after the
fall of the Roman Empire, ceased to expand or progress, became mixed
up with fanciful notions, and only recovered when a knowledge of
ancient science and thought was restored in the fifteenth century.
But in geography we can more easily see than in other sciences
the exact nature of the disturbing influence which prevented the
acquisition of new knowledge.

[Footnote 1: It is fair to add that Professor Miller's researches
have shown that some of the "unscientific" qualities of the mediaeval
_mappoe mundi_ were due to Roman models.]

Briefly put, th