critically focussed its varied historical aspects by a masterly analysis in chapters viii and ix of his Essai sur l'histoire des Tou-kiue occidentaux 29. Our references to the events which affected the Tarim Basin and Kashgar may therefore be brief.
For more than two decades after the recovery of the ' Four Garrisons', Chinese policy towards the West appears to have been purely defensive. The internal conditions of the empire during the usurpation of the Empress Wu (684-705 A. D.), and still more the revival of the power of the Northern Turks under the great chief Kapagan Kagan, called Mo-cho in the Chinese Annals (691-716 A. D.), fully account for this. In the year 699 all the tribes of the Western Turks acknowledged the sovereignty of Kapagan Kagan, and it was consequently to the latter and not to the Chinese court that the princes of the Oxus region and Sogdiana turned for help against the rising tide of Arab invasion 30. During the years 705-715 a series of brilliant expeditions under the leadership of the famous Qutayba ibn Muslim carried the Muhammadan arms victoriously across Balkh to Bukhara, Samarkand, and Farghana. The armed intervention of the Kagan of the Northern Turks, residing far away on the banks of the Orkhon, failed to afford protection. Thus when, in the year 714, the Chinese, evidently in pursuance of the more active foreign policy initiated by the Emperor Hsüan-tsung, recovered their supremacy over the Western Turks, they soon found themselves face to face with the Arabs 31.
The revolt of Qutayba against the Khalifa Sulayman, and his subsequent death in the year 715, appear to have occurred most opportunely for the ends of Chinese policy. On the Muhammadan side Tabari's Chronicle informs us of a victorious expedition of Qutayba to Kashgar, ' a city near the Chinese frontier ', effected evidently at the commencement of Sulayman's reign (715-717 A. D.) 32. On the other hand Chinese historical records show that in the year 715 the Chinese general Chang Hsiao-sung, setting forth from the Protectorate of An-hsi or Kucha, and supported by neighbouring tributary tribes, succeeded in forcibly reinstating the king of Pahan-na or Farghana, whom the Arabs and Tibetans in alliance had driven from his territory. This initial success of the Chinese was promptly followed by offers of submission from a number of states in the ' Western Regions ', extending from Ta yüan, or Täshkend, to Chitin or the Kabul Valley 33.
The rebellion of the Turgäsh tribe of the Western Turks brought once more, in 717, the allied Arabs and Tibetans into the territory of the ' Four Garrisons', where the towns of UshTurfan and Ak-su, on the route between Kashgar and Kucha, were besieged by them 34. The Chinese sgraffito discovered by me in the Endere temple, with its date of 719 A. D., shows that at about the same time Tibetan inroads continued into the southern portion of the Tarim Basin 35. But Chinese diplomacy soon succeeded in checking the danger from the side of the Turgäsh ; and though effective. control over the territory properly belonging to the Western Turks was not recovered by the Chinese until 738, the reign of Hsüan-tsung was a period of prolonged consolidation for their power within the ' Four Garrisons '. Without the firm position thus secured in the Tarim Basin it would have been impossible for Chinese policy to exercise that remarkable activity, diplomatic and military, in distant territories to the west and south-west, which a series of interesting records and diplomatic documents attest for the years 719 to 75186.
28 See Turcs occid., pp. 281, 299.
S0 See ibid., pp. 282 sq., 288 sqq.
S1 Compare ibid., pp. 283, 29o.
32 Compare Bretschneider, Mediaeval Researches, ii. p. 46,
quoting Zotenberg's translation of Tabari, iv. p. 198.
83 See Turcs occid., pp. 148 note, 291.
3' See ibid., p. 284, note.
85 See below chap. xIi.
36 See regarding this extension of Chinese influence,
Turcs occid., pp. 292-7.