These four centuries, the twelfth, thirteenth, fourteenth, and fifteenth, constitute what is called the Age of Discovery. The fifteenth century marks its greatest development; and in the last decade of that century it enters on its final stage, consequent on the discovery of America.
This period was an Age of Discovery in a wider sense than the word denotes when associated with maritime enterprise only. It beheld signal discoveries in the arts and sciences-the result of a renewed intellectual activity contrasting vividly with the stagnation or retrogression of the ten centuries preceding. It witnessed the rise and development of Gothic architecture, in connexion with the foundation or rebuilding of cathedrals and monasteries; the beginnings of modern painting, sculpture, and .music; the institution of universities; the revival of Greek philosophy and Roman law; and some premature strivings after freedom of thought in religion, sternly repressed at the time, but destined finally to triumph in the Reformation. All these movements were in fact signs of increased vitality and influence on the part of Roman Christianity; and this cause stimulated geographical discovery in more than one way. Various religious and military Orders now assumed, and vigorously exercised, the function of spreading Christianity beyond the limits of the Roman Empire. By the end of the tenth century, the Danes, Norwegians, Swedes, Poles, and Hungarians had already been partly converted. During the twelfth century, the borders of the Roman faith were greatly enlarged. Missionary enterprise was extended to the Pomeranians and other Slavonic peoples, the Finns, Lieflanders, and Esthonians. The Russians had already been christianised by preachers of the Greek Church; Nestorians had penetrated Central Asia, and converted a powerful Khan who himself became a priest, and whose fame rapidly overspread Christendom under the name of Presbyter or "Prester" John. Prester John was succeeded by a son, or brother, who bore the name of David; but Genghis Khan attacked him, and towards the end of the twelfth century put an end to the Christian Khanate. In the thirteenth century, Roman missionaries sought to recover the ground thus lost, and Roman envoys made their way through Central Asia, though the Catholic faith never obtained in these Eastern parts more than an imperfect reception and a precarious footing. Traders and other travellers brought the Far East into communication with Europe in other ways; and Marco Polo, a Venetian adventurer who had found employment at the Great Khan's court, even compiled a handbook to the East for the use of European visitors.
While inland discovery and the spread of Christianity were thus proceeding concurrently in the North of Europe and Central Asia, a process somewhat similar in principle, but different in its aspect, was going on in the South, where the Mediterranean Sea divided the Christian world from the powerful "Saracens," or Mohammadans of