The most famous of all medieval travelers were Nicolo and Maffeo Polo, and Nicolo's son, Marco. These Venetian merchants set out for Asia in 1271 A.D., and after an adventurous journey reached the court of Kublai Khan at Peking. [7] The Mongol ruler, who seems to have been anxious to introduce Christianity and European culture among his people, received them in a friendly manner, and they amassed much wealth by trade. Marco entered the khan's service and went on several expeditions to distant parts of the Mongol realm. Many years passed before Kublai would allow his useful guests to return to Europe. They sailed at length from Zaitun, a Chinese seaport, skirted the coast of southeastern Asia and India, and then made their way overland to the Mediterranean. When the travelers reached Venice after an absence of twenty-four years, their relatives were slow to recognize in them the long-lost Polos.
[Illustration: GEOGRAPHICAL KNOWLEDGE DURING THE MIDDLE AGES
THE WORLD ACCORDING TO COSMAS INDICOPLEUSTES, 535 A.D.
THE HEREFORD MAP, 1280 A.D.]
MARCO POLO'S BOOK
The story of the Polos, as written down at Marco's dictation, became one of the most popular works of the Middle Ages. In this book Europe read of far Cathay (China), with its wealth, its huge cities, and swarming population, of mysterious and secluded Tibet, of Burma, Siam, and Cochin- China, with their palaces and pagodas, of the East Indies, famed for spices, of Ceylon, abounding in pearls, and of India, little known since the days of Alexander the Great. Even Cipango (Japan) Marco described from hearsay as an island whose people were white, civilized, and so rich in gold that the royal palace was roofed and paved with that metal. The accounts of these countries naturally made Europeans more eager than ever to reach the East.
219. AIDS TO EXPLORATION
THE COMPASS
The new knowledge gained by European peoples about the land routes of Asia was accompanied by much progress in the art of ocean navigation. First in importance came the compass to guide explorers across the waters of the world. The Chinese appear to have discovered that a needle, when rubbed with a lodestone, has the mysterious power of pointing to the north. The Arabs may have introduced this rude form of the compass among Mediterranean sailors. The instrument, improved by being balanced on a pivot so that it would not be affected by choppy seas, seems to have been generally used by Europeans as early as the thirteenth century. It greatly aided sailors by enabling them to find their bearings in murky weather and on starless nights. The compass, though useful, was not indispensable; without its help the Northmen had made their distant expeditions in the Atlantic.
NAUTICAL INSTRUMENTS
The astrolabe, which the Greeks had invented and used for astronomical purposes, also came into Europe through the Arabs. It was employed to calculate latitudes by observation of the height of the sun above the horizon. Other instruments that found a place on shipboard were the hour- glass, minute-glass, and sun-dial. A rude form of the log was used as a means of estimating the speed of a vessel, and so of finding roughly the longitude.
[Illustration: AN ASTROLABE]