It is to Chinese sources that we must turn for an account of the tribes which overthrew GrÆco-Bactrian rule, and were a constant thorn in the side of the Parthian Empire. These sources, with faint sidelights thrown on an obscure period by allusions to be found in classic authors, enable us to bridge a gap of several centuries replete with events which exercised a lasting influence on the history of Central Asia.

The Chow dynasty ruled from B.C. 1122 to B.C. 250.31 After its fall China split up into a vast number of nearly independent principalities, and the reigning sovereign enjoyed but little power. The Tsin succeeded in gaining the foremost rank as feudatories, and finally restored the authority of the central power. Their aim was not achieved without a desperate struggle with their rivals. In the course of the resulting civil war Tsin Chi Hwang-ti began his reign. He was the Louis XI. of the Chinese monarchy, and brought force and stratagem by turns to bear on the task of restoring the imperial prestige.32 When he found himself master at home, he turned his attention to the task of protecting his frontier from aggressors. Of these, the Hiung-nu, a Tartar tribe whose habitat was Eastern Mongolia, were the most troublesome. He carried the war into the enemy’s camp by despatching an army across the great Gobi Desert, with orders to establish a strong place at Hami.33 In B.C. 250 he commenced a work which had a more lasting effect in repressing their invasion. This was the Great Wall of China, which starts from the Shan-hi Pass and ends at the Chin-YÜ barriers, a distance of not less than 1500 miles. The Hiung-nu, like their kinsmen the Mongols of Chingiz and of Timur, fought on horseback, and their plan of campaign was simply a succession of raids followed by speedy retreats. This stupendous barrier intimidated them, and turned westwards the tide of their migration. Thus the Great Wall, which it is the fashion to decry as a monument of misplaced labour, was a most important factor in the history of Central Asia. At this epoch the Sakas were settled in Hexapolis, to the east of the Pamirs; while the Usuns dwelt on the southern side of Lake Lob, separated from the Sakas by the Uighurs. About B.C. 300 the empire of the YuÉ-Chi,34 who were a branch of the Tung-nu, or Eastern Tartars, extended most probably from the Muztagh Mountains on the north to the Kuen-lun Mountains on the south, and from the Upper Hoang-ho in Shan-si on the east to KochÉ and Khotan on the west.35

About B.C. 200 a war broke out between the Tung-nu and the Hiung-nu (the Western Tartars or Huns), their neighbours. MothÉ, the chief of these latter, falling on the Eastern Tartars unawares, utterly defeated them and drove the YuÉ-Chi from their kingdom. The latter fled to the banks of the Ili River, while MothÉ pushed his conquests as far as the Volga on the west and the border provinces of China eastwards. The Emperor Kao-tsu (B.C. 202–194), founder of the famous Han dynasty, who had achieved the subjugation of the whole of China, was alarmed at the progress of MothÉ, and marched against him. His troops were, however, surrounded by MothÉ’s colossal hordes in the north of the province of Shan-si, and only escaped destruction by the employment of a ruse.36 On the departure of the Chinese army MothÉ set out for Tartary. For upwards of fifty years the power of Hiung-nu sustained no check. They continued to press down on the YuÉ-Chi, who, after suffering a further crushing defeat, broke into separate hordes. The lesser division, or “Little YuÉ-Chi,” passed into Tibet. The “Great YuÉ-Chi’s” first movement was westwards to the banks of the Ili, but finding the Usun too strong for them, they wandered in a southerly direction, and finally descended upon Kashghar, Yarkand, and Khotan, whence they displaced the Sakas (B.C. 163). The latter, on their expulsion from Soghdiana, invaded Bactria, and from this period until the fall of the GrÆco-Bactrian kingdom the Greeks had to deal with both Sakas and Parthians. It would seem that the latter were alternately friends and foes. This intercourse possibly accounts for the Parthian characteristics found on the early Saka coins of India.37

The Sakas were driven towards the Pamirs and the Tien-shan. One branch of them fled to Zungaria, while the majority remained in Hexapolis and intermixed with the Uighurs, who had been for a long period masters of that country. A third branch turned their steps towards the upper valleys of the Yarkand Darya. Some of these fugitives established themselves in the little Iranian States of Serikul and Shugnan, where appreciable traces of their language still survive.38 Others crossed the Karakorum, and invaded the north-east of India.

At this epoch the Chinese obtained a glimpse of the position of Western Asia through the medium of prisoners taken from the Hiung-nu. From them they learned that the YuÉ-Chi had suffered defeat at the hands of the Huns, and been compelled to migrate far from their ancient abode. They had, however, become very powerful in Bactria and Transoxiana, and had conquered Ta-hia (Khorasan), establishing themselves finally there in spite of the Parthian resistance. The Emperor Wu-ti eagerly desired an alliance with the YuÉ-Chi against their common enemy the Hiung-nu. With this view he sent his general Chang-Kien on an embassy to the prince, accompanied by a suite of a hundred attendants. The envoy, however, had the misfortune to fall into the hands of the Huns while traversing their territory, and escaped only after a ten years’ imprisonment. On joining the YuÉ-Chi, he found them employed in driving the Sakas out of Soghdiana. He accompanied them on a victorious expedition, and then returned to China, with two followers, sole survivors of his cortege. The emperor expressed his appreciation of the intelligence brought by Chang-Kien regarding Central Asian events, by elevating him to an important post. These events led to the establishment of direct commercial intercourse between China and the West, which, however, the Huns did their utmost to interrupt.

A collation of the Chinese annals, the classic authors, and the coins which have come down to us, would render it tolerably certain that the Greeks lost their hold on Soghdiana in B.C. 163; that a little later they were deprived of Bactria by the Sakas, and of Margiana by the Parthians. From this period their dominion was limited to the southern slopes of the Indian Caucasus. That the GrÆco-Bactrian Empire had attained a high degree of natural civilisation, and, indeed, of artistic culture, is evidenced by the purity of design and the excellence of workmanship displayed by the later coins.

The Bactrians displaced by the Sakas fled eastward, and settled in the confines of Bokhara, and the surrounding countries.39 But the dominion of their opponents in Bactria was not destined to be of long duration, for in B.C. 120 the YuÉ-Chi, who had already overrun the ancient territory of the Sakas, began to pour into Bactria.

After expelling the Sakas, and the remnant of the GrÆco-Bactrians,40 the YuÉ-Chi settled in that part of Central Asia which is named Tokharistan, after their tribal appellation, and which included Balkh, Kunduz, Hisar, Bolor, Wakhan, and Badakhshan. Meanwhile the Sakas retreated southwards, and occupied in turn Kiphin, Soghdiana, Arachosia (Kandahar), and Drangiana (Sistan).41

Their invasion of India was directly due to the usurpation of their country by the YuÉ-Chi. The latter parcelled Bactria out among their five clans.42 Each had its own capital, but the only YuÉ-Chi headquarters which has been identified is Bamian, at the foot of the northern slope of the Hindu Kush.

The partition continued in force for nearly a century, during which repeated collisions occurred between the YuÉ-Chi and the Parthians. In B.C. 30 the chief of one of the clans, the Kwei-shuang, subdued the rest, and assumed sovereignty over the whole race. They became thenceforward known by the name of the conquering clan, which in course of time was modified to Kushan, and appears so inscribed on their coins. The recent overthrow of their most persistent enemies the Hiung-nu rendered the more easy the task of consolidating their power, for in the year B.C. 71 the reigning Chinese emperor had administered a crushing defeat on the Huns, who were in B.C. 60 finally enrolled into the Chinese Empire. They thus became masters of all those countries which go to form Turkestan, Eastern Iran, and Afghanistan. The YuÉ-Chi, or Kushans, relieved of this incubus, turned their arms towards the south, crossed the Paropanisus, and overran Kabul, which belonged in part to the ArsacidÆ, and in part to the Sakas, driving the latter out of their kingdom of Kiphin.43

At the dawn of the Christian era the Kushans were a foremost power in Central Asia. The Romans deigned to treat with them as an established empire. Mark Antony, for example, sent ambassadors to Bactria, whose chiefs (all Kushans) were represented at Rome by an envoy under Augustus; while later, in the reign of Trojan and Adrian, they sent ambassadors to solicit an alliance against the Parthians.44 From Chinese sources we learn that in the year A.D. 98 their general Panchao45 was received during an expedition to the Caspian by the YuÉ-Chi, and that they recognised the imperial sovereignty by annual presents.

Their power was not destined to endure for long. By the end of the third century A.D. they had lost most of their conquests in the south of Paropamisus, including Kashmir. They were finally expelled from Bactria itself by the Ephthalites, or White Huns, about the year A.D. 430.

The last Kushan king of whom we find a trace in history was named Kitolo. He conquered Gandhara, or Kandahar; but was forced to return to his own dominion by an irruption of White Huns. The son whom he left in charge of the new province established his capital at Peshawar.46 The name of the founder of the Little YuÉ-Chi, as they were afterwards called, survives in the title of Shah Kator, chief of Chitral.

The Ephthalites, or White Huns, who, as we have seen, in the year A.D. 430 became possessed of Bactria, were in all probability of the same stock as the YuÉ-Chi. They are known to history under a great variety of names, such as Naphthalites, Hayathila, and Yetha. This last is the name by which they are known to the Chinese, who always most carefully distinguish between the Yetha and the YuÉ-Chi.47 The Yetha were of Tartaric origin, and are described as having anciently lived to the north of the Great Wall, and to have advanced southwards about the first century of our era. They then came under the domination of the Juen-Juen,48 but emerging from this, they ultimately became masters of an empire which extended to the borders of Persia, and comprised Kiphin, Kharashar, Kashghar, and Khotan. The arrival of the Yetha in Transoxiana about the year 425 of our era was the result of those migrations of Tartar peoples which took place in Central Asia at the beginning of the fifth century. About 360 the Juen-Juen advancing westwards became masters of all Tartary.49 One of their kings, Tulun by name, who reigned at the beginning of the fifth century, carried his conquest from Corea to the confines of Europe. It was owing to these conquests that the various Hunnish tribes, driven from their ancient habitats by these new invaders, swept into Transoxiana in 425 (i.e. the Ephthalites), and into Europe, under Attila, in 430. On the appearance of the White Huns in the Oxus districts that country had been for five centuries in the possession of the YuÉ-Chi, or Kushans, as we have seen above, and they occupied the land for upwards of 130 years (425 to 557), during which period they were in close contact with the Sasanides of Persia. The Kushans did not, however, immediately disappear from Central Asia, for we find references after this date in Chinese authors to small Kushan principalities in the Upper Oxus and Farghana.