them eastward, founding sees in Persia and Turkestan, and ultimately spreading as far as Pekin.  There was a certain revival of their missionary activity under the Mongol Khans, but the restricted nature of the language in which their reports were written prevented them from having any effect upon geographical knowledge, except in one particular, which is of some interest.  The fate of the Lost Ten Tribes of Israel has always excited interest, and a legend arose that they had been converted to Christianity, and existed somewhere in the East under a king who was also a priest, and known as Prester John.  Now, in the reports brought by some of the Nestorian priests westward, it was stated that one of the Mongol princes named Ung Khan had adopted Christianity, and as this in Syriac sounded something like “John the Cohen,” or “Priest,” he was identified with the Prester John of legend, and for a long time one of the objects of travel in the East was to discover this Christian kingdom.  It was, however, later ascertained that there did exist such a Christian kingdom in Abyssinia, and as owing to the erroneous views of Ptolemy, followed by the Arabs, Abyssinia was considered to spread towards Farther India, the land of Prester John was identified in Abyssinia.  We shall see later on how this error helped the progress of geographical discovery.

The total addition of these mediaeval travels to geographical knowledge consisted mainly in the addition of a wider extent of land in China, and the archipelago of Japan, or Cipangu, to the map of the world.  The accompanying map displays the various travels and voyages of importance, and will enable the reader to understand how students of geography, who added on to Ptolemy’s estimate of the extent of the world east and west the new knowledge acquired by Marco Polo, would still further decrease the distance westward between Europe and Cipangu, and thus prepare men for the voyage of Columbus.

[Authorities: Sir Henry Yule, Cathay and the Way Thither, 1865; The Book of Ser Marco Polo, 1875.]

CHAPTER V

ROADS AND COMMERCE

We have now conducted the course of our inquiries through ancient times and the Middle Ages up to the very eve of the great discoveries of the fifteenth and sixteenth centuries, and we have roughly indicated what men had learned about the earth during that long period, and, how they learned it.  But it still remains to consider by what means they arrived at their knowledge, and why they sought for it.  To some extent we may have answered the latter question when dealing with the progress of conquest, but men did not conquer merely for the sake of conquest.  We have still to consider the material advantages attaching to warfare.  Again when men go on their wars of discovery, they have to progress, for the most part, along paths already beaten for them by the natives of the country they intend to conquer; and often when they have succeeded in warfare, they have to consolidate their rule by creating new and more appropriate means of communication.  To put it shortly, we have still to discuss the roads of the ancient and mediaeval worlds, and the commerce for which those roads were mainly used.