Darius was at liberty to deduce whatever explanation he chose. He retreated, the Scythians hounding his army on. He found his bridge over the Bosphorus safe, and returned to Persia to prepare the Athenian expedition that ended at Marathon. The Scythians remained: they were left leading their flocks as of old over the unconquerable steppes. By these echoes of clashings with other nations, the first-known streams of Mongol outflow are dimly followed to the Caucasus Mountains and the Black Sea on the south and west, bounding Scythia; to the Hoang-ho Valley, in which were living the metamorphosed Chinese. But the rolling hills south of Lake Baikal, the source of the race-stream, still poured out fresh hordes, which periodically overflowed in roving nomad bands, harrying the plainsmen. While the feudal states of China struggled and fought among themselves, now coalescing under the “Wu-pa,” the five dictators, now uniting under a Prince Hwan of Shan-tung into a temporary Chinese Shogunate, there came down upon the fertile lands and populous cities wild horsemen, sparing none, burning, looting, riding away. “The Hiung-nu descended on us,” appears again and again in the history. At length, about 246 B.C., arose the short but glorious dynasty of Ts’in, under China’s king, Shi-hwang-ti. He was a man of action. He compacted a centralized monarchy from the many princedoms, drove back the nomad Hiung-nu beyond the Yellow River, built the Great Wall, and by his glorious exploits blazoned into Europe’s vocabulary, the word China--Ts’in. In Sz-ma Ts’ien’s history, a striking incident, revealing the Great Emperor’s limitations, is graphically told. “Li-se, the councillor, said, ‘Of old, the Empire was divided and troubled. There was nobody who could unite it. Therefore did many lords reign at a time. For this, the readers of books speak of old times to cry down these. They encourage the people to forge calumnies. Your subject proposes that all the official histories be burned. The books not proscribed shall be those of medicine, of divination, of agriculture. If any want to study laws, let them take the office-holders as masters.’” The decree was “approved.” The old books of annals, the Confucian Commentaries, the Odes and the Rituals, to the suppressed execration of the learned, fed the flames. The literati who protested were warmed, themselves, over the same fires. But despite Shi-hwang-ti’s signal defeat of the five coalescing tribes, and the eighty-two thousand severed heads; despite the victories in 214 B.C., the Hiung-nu Empire grew in power, until it extended from Corea to Tibet. The Chinese “Han” Dynasty, even under the peasant-founder, Lin-pang, who had proven himself a thorough soldier, was constantly harried. The loss of the old literature continued to be mourned, which argues some plane of general appreciation. The Minister urged the recall of the Ts’in philosophers and the reproduction of the burned books.