diaeval geography may be
fairly said to end, for within eighty years of his death began
the activity of Prince Henry the Navigator, with whom the modern
epoch begins.

Meanwhile India had become somewhat better known, chiefly by the
travels of wandering friars, who visited it mainly for the sake of
the shrine of St. Thomas, who was supposed to have been martyred
in India. Mention should also be made of the early spread of the
Nestorian Church throughout Central Asia. As early as the seventh
century the Syrian Christians who followed the views of Nestorius
began spreading 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 betw