Of the nature of that intercourse in its earlier period, there exists a monument that speaks volumes. That is no other than the Great Wall; which, hugest of the works of man, stretches along the northern frontier of China proper for one thousand five hundred miles from the sea to the desert of Gobi. Erected 255 B.C. it shows that even at that early date the enemies most dreaded by the Chinese were on the north. Yet how signally it failed to effect its purpose! For since that epoch the provinces of Northern China have passed no fewer than seven centuries under Tartar sway. Two Tartar dynasties have succeeded in subjugating the whole empire, and they have transmitted beyond the seas a reputation which quite eclipses the fame of China's ancient sovereigns. In fact, that which first made China known to the western world was its conquest by the Mongols in the thirteenth century. Barbarous nomads, with longing eyes forever directed to the sunny plains of the south, they also conquered India, bringing under their sceptre the two richest regions of the globe. Of Genghis and Kubla, it may be asserted that they realized a more extended dominion than Alexander, Caesar, or Napoleon ever dreamed of. But "Extended empire, like expanded gold, Exchanges solid strength for feeble splendor." Their tenure of China was of short duration,--less than a century. In India, however, their successors, the great Moguls, continued to maintain a semblance of sovereignty even down to our own times, when they were wiped from the blackboard for having taken part in the Sepoy mutiny. Liberal beyond precedent, Kubla Khan encouraged the establishment of a Christian bishopric, in which John de Monte Corvino was the first representative of the Holy See. He also welcomed those adventurous Italians, the Polos, and sought to make use of them to open communication with Europe. Yet we cannot forbear to express a doubt, whether, aside from the Christian religion, Europe in that age had much in the way of civilization to impart to China. Three of the native dynasties, which preceded the Mongol conquest, made themselves famous by advancing the interests of civilization. The house of Han (B.C. 202-A.D. 221) restored the sacred books, which the builder of the Great Wall had destroyed in order to obliterate all traces of feudalism and make the people submit to a centralized government. Even down to the present day, the Chinese are proud to describe themselves as "sons of Han." The house of Tang, A.D. 618-908, is noted above all for the literary style of its prose-writers and the genius of its poets. In South China the people are fond of calling themselves "sons of Tang." The house of Sung, A.D. 970-1127, shows a galaxy of philosophers and scholars, whose expositions and speculations are accepted as the standard of orthodoxy. More acute reasoners it would be difficult to find in any country; and in the line of erudition they have never been surpassed.