Kao Chü-hui obviously implies that they, too, at one time held the mountain tracts through which the preceding rapid survey has taken us. At his own time these must have belonged to the Hui-ho,
or Uigurs, 4, then in possession of Kan-chou. But what is of particular historical interest
for us is the fact that in Kao Chü-hui's days local tradition evidently still remembered those Nan-shan valleys and uplands having served as grazing grounds for the ancient Little Yüeh-chih of Han times. An important passage of Ssû-ma Ch'ien's history tells us that when the Great Yüeh-chin, before masters of the whole region between Liang-chou and Tun-huang, had been defeated by the Hsiung-nu and had started about the middle of the second century B. c. on the great exodus which was to carry them to the Oxus and ultimately, as the Indo-Scythians, to the Indus, a small number among them, unable to depart, remained behind and took refuge
among the Chiang X of the Nan-shan (j( ; they received the designation of the Little Yüeh-
chih A A'.1°
From the Later Han Annals we learn that the Little Yüeh-chih, after having found a refuge among the Chiang or Tibetan tribes in the Hsi-ning region, made their submission to the Chinese when the Hsiung-nu had been driven from the Kan-su borders in 121 B. C, and that subsequently a portion of them regained their old seats near Kan-chou.17 As late as A.D. 189 a reference is made in the same Annals to a revolt which took place among the Little Yiieh-chih settled about Kan=chou against the Chinese administration."S There is reason to believe that the object which guided the imperial authorities in this repatriation of a portion of the Little Yüeh-chih was the same as that underlying the later settlement on this ground of the Sha-t`o and Sarö and Shera Yögurs, i. e. to secure auxiliaries for the defence of the border more warlike than the local Chinese. But other remnants of the Yiieh-chih evidently survived in the mountains much further to the west. Thus the Wei lio, composed between A. D. 239 and 265, mentions Yüeh-chih remnants, along with various tribes evidently of Tibetan descent, as living in the ` mountains of the South ' that stretch from Tun-huang to the Ts`ung-ling.' Kao Chü-hui, too, when passing in A.D. 939 through the territory of the Chung-yün
1'iJi , a tribe inhabiting the desert mountains west of Tun-huang, records the tradition that ` the
Chung-yün are a branch which has remained of the Little Yiieh-chip '.20 They are described as brave and warlike men, dreaded by the inhabitants of Kua-chou and Sha-chou.
These historical notices, mere glimpses as they are, will help us to appreciate better the important bearing which the favourable physical conditions prevailing in the valleys and uplands of the Central Nan-shan must have had upon the history of the territory stretching along its northern foot from Liang-chou to Su-chou and beyond. Were it not for the abundant summer grazing grounds to be found there, this narrow belt of cultivable ground between the foot of the Richthofen Range and the arid sandy wastes adjoining it northward would certainly not have played the part it has in history as a coveted goal of conquest for a long succession of nomadic nations such as the Wu-sun, Yiieh-chih, and Hsiung-nu, Tibetans and Uigurs, Tanguts and Mongols.
For the Chinese, indeed, who ever since their first occupation more than two thousand years ago have struggled to keep nomadic invaders out of this ` land of passage ', its possession was indispensable, quite irrespective of the physical aspects of those mountains ; they needed it because it
following the downfall of the 'I sang dynasty, cf. Chavannes, Turcs occid., p. 272.
16 Cf. Chavannes, T'oung pao, r905, p. 527, note r. As regards the extent of the territories originally subject to the Yiieh-chih before their expulsion by the Hsiung-nu, cf. Franke, Zur Kennlniss der Türkvölker, p. 27, quoting Ssû-ma Ch'ien's Shi chi, chap. cxxiii ; see also /bid., p. 26, for a correspond
ing statement of the Later IIan Annals.
17 See Franke, Zur Kenniniss der Trirkvölker, p. 26, quoting Hou Han shu, chap. cxvir.
18 Cf. Franke, loc. cil., p. 27.
19 See Chavannes, T`oungpao, 1905, pp. 526 sqq.
'0 Cf. Chavannes, ibid., p. 528, note ; Rémusat, Ville de Kholan, p. 78.
Little Yüehchih left behind in Nan-shan.
Little Yüehchih under Later Han and after.
Little Ytiehchih in mountains near Tunhuang.
Importance of Nan-shan grazing.
Nan-shan on flank of Chinese ' passage land '.