¹ The Tibetans cut the Central Asian line in the Tarim Basin, which thev first occupied circa A.D. 670–92, and then again from circa A.D. 790 until the middle of the ninth century, when the Uigurs broke into the corridor from the opposite flank and turned the Tibetans out of it.

¹ Pumpelly, R.: Explorations in Turkestan (published at Washington, D.C., by the Carnegie Institution: I, Expedition of 1903 = Publication 26, 1905Google Scholar; II, Expedition of 1904 = Publication 73, 1908, 2 vols.).

² Rostovtzev, M.: Iranians and Greeks in South Russia (Oxford, 1922, Clarendon Press).Google Scholar

¹ From the point of view of what follows, it is worth noting that the Islamic wave spread from the Oxus-Jaxartes Basin in another direction simultaneously. By the first quarter of the tenth century after Christ, Islamic influences from Transoxania, crossing the Steppe along the route of the present Tashkend-Orenburg Railway, had resulted in the conversion of the White Bulgarians, who held the key to the Volga Basin at the junction of the Volga with the Kama. The same wave gradually spread over the Bashkirs of the Ural region and the Tatars of Siberia.

¹ Unless the Avesta and the Persian Epic originated among the Iranians of the Oxus-Jaxartes Basin and not among those of the Iranian Plateau.

² The Chagatai appanage included the Oxus-Jaxartes and the Tarim Basins (i.e. the whole of the Central Asiancorridor) together with that sector of the Eurasian Steppe (then called Moghulistan) which lies immediately to the north of them.

¹ As early as A.D. 713 Musa had occupied Septimania (the strip of French coast between the Pyrennees and the Rhone which had previously belonged to the Visigothic kingdom of Spain), while Qutaybahad penetrated far beyond the bounds of Khurasan, into Khwarizm and Farghana. It has been shown, however, by Mr. H. A. B. Gibb in The Arab Conquests in Central Asia (London, 1923, Royal Asiatic Society) that the campaigns of Qutayba in the Oxus-Jaxartes Basin, though brilliant and extensive, were superficial. Their results were almost entirely lost after his death, and, by the beginning of the year 721, the Arab holdings in Tukharistan and Transoxania beyond the Iranian Plateau were as small as the Arab holdings at the same date in Gaul beyond the Pyrennees.

² Assuming that Zoroastrianism originated in Media and not in Bactria (in which latter case it would have been a native product of the Oxus-Jaxartes Basin).

¹ In climate and vegetation the Elbruz range may be considered as being a detached and remote enclave of Northern Europe, and the sub-tropical coastal belt between the Elbruz and the Caspian as a similar enclave of India. Compare the equally curious enclave of Mediterranean climate along the south-eastern littoral of the Black Sea, which also faces northward.

² At that time the main stream of the Oxus may possibly have flowed into the Caspian, and this would have afforded water transport all the way from Daylam to Sughd via Khwarism. But, in any case, there was always a caravan-route between Khwarism and the eastern coast of the Caspian.

¹ For the differences in this respect see pp. 257–62 below.

¹ Chapter 52 (vol. vi of J. B. Bury's smaller edition of the Declire and Fall of the Roman Empire).

¹ Both under Umayyad sovereignty in Spain and under ‘Abbasid sovereignty elsewhere.

¹ Buddhism, which travelled eastward and south-eastward along the corridor to the Far Eastern World, does not appear to have penetrated the steppe-country to the north.

¹ Just as in the eleventh century the Saljuqs and the Normans broke simultaneously upon the Byzantine World.

¹ It might, of course, be suggested that a clue is also to be found in the much greater distance of Gaul than that of the Oxus-Jaxartes Basin from the Syrian centre of the Umayyad Power, and it even might be argued that this geographical difference was the capital factor. It is true that the distance from Damascus to Narbonne overland, via North Africa and the Straits of Gibraltar, is approximately twice as great as the distance from Damascus overland to Merv. The significance of this fact has to be discounted, however, by two considerations. In the first place the north-western (but not the north-eastern) front was connected with the main base of the Arab Empire by an alternative water-route, extending along the length of the Mediterranean from the Syrian ports or Alexandria to Barcelona, Empurias, or Agde. It would be interesting to know to what extent (if any) the Constantinople Government made use of its naval ascendency in the Mediterranean at this period in order to deny to the Arabs the employment of this maritime route for the conduct of their Gallic campaigns. As far as the present writer is aware, no precise evidence on this point has been preserved; but (given the probable relative strength of Byzantine and Arab seapower in the eighth century) it seems unlikely that the Byzantines can have blocked this route altogether, and—so far as it was available—it must have been both quicker and easier (given the relative development, at that period, of land and water transport facilities) than the quantitatively shorter overland route from Syria to Khurasan. In the second place, however, it is doubtful whether the comparative difficulty or ease of communication between Syria and the frontier war-zones was a military factor of first-rate importance; for the historical records indicate that (in the Umayyad, as in its predecessor the Achæmenid, Empire) imperial troops from the centre seldom put in an appearance on the borders. Border-campaigns, even when planned on an ambitious scale, were generally dependent almost entirely upon local man-power, drawn partly from Arab military colonies (previously planted in the frontier-provinces of the time) and partly from loyal elements recruited among the provincial population. The man-power of the Arab colonies was, of course, limited; but, when an additional military effort was desired, the frontier commanders seem normally to have met the need, not by calling upon Damascus for Arab reinforcements, but by drawing more largely upon the non-Arab provincial elements. The unusual strength of the Berber levies from North-West Africa and of the Iranian levies from Khurasan was a marked feature in the armies with which Qutayba and ‘Abdu'r-rahman invaded Transoxania and Gaul respectively. For these several reasons, it would be rash to rely too much upon the factor of distance in seeking for an explanation of the failure of the Arabs in Gaul in contrast to their contemporary success in the Oxus-Jaxartes Basin.

Addendum.—Mr. H. A. E. Gibb, with whom the writer has had the benefit of discussing the considerations advanced above, suggests that they ought not to be pressed too far and that the factor of distance may have been more important than the writer had supposed. Without having re-examined the evidence in detail, Mr. Gibb is under the impression that evidence is lacking to show that the Arabs used the maritime line of communication between Syria and Spain, and that such evidence as exists points rather to the land route via North Africa as being normally employed. In other words, the sea-power which the Arabs mustered in the Levant for their campaigns against Rum was not available (or, at any rate, was not used) to assist them in maintaining their north-western front in Gaul; and if, for this purpose, they used the land route, that placed their communications at the mercy of the Berbers in Africa (not to speak of their troubles with Berber troops and colonists in Spain itself). In consequence, Spain was being constantly left in the air, and a case of this occurred in A.D. 740 (that is, within the critical period after the indecisive Battle of Tours). In contrast to this, Hisham was able to reinforce Khurasan with troops from ‘Iraq after the Battle of the Pass (in itself, a more serious reverse than the Battle of Tours), and apparently with troops from Syria, as well, at the critical moment in the revolt of Harith. [For the special position of the Syrian troops, Mr. Gibb refers to Lammens, H.: Études sur le Règne du Calife Omaiyade Mo'awia I: Beyrut, 1906 (pp. 267–8)Google Scholar.] It is true that Syrian troops, with Egyptian reinforcements, were likewise sent to Africa in A.D. 740 or 741, but that was for the purpose of crushing the local Berber revolt, not of reinforcing Spain, and in any case these troops were crushingly defeated by the Berbers in Morocco. Mr. Gibb also suggests that a concentration of effort was a further factor in the ultimate success of the Arabs on the north-eastern front. Besides the expansion into the Oxus-Jaxartes Basin via the Iranian Plateau, there had been an expansion via the Persian Gulf into the lower basin of the Indus, and this had been at its height during the period of Qutayba's campaigns. On the other hand, from the time of Junayd's transfer to Khurasan, the Arabs merely maintained their positions in Sind, and the whole of their striking force in the east was directed towards the Oxus and Jaxartes.

¹ e.g. the embassy which arrived in A.D. 568 at the Court of Constantinople from the Khaqan of the nomad empire of the Turks included a Transoxanian prince, whose object was to open up a trade-route north of the Caspian, and therefore beyond the reach of interference by the Persians. It seems probable that this embassy was sent on the initiative of the Transoxanian merchants, though it was headed by a representative of their suzerain, the Turkish Khaqan.

¹ No record of this event survives, but some modern historians have conjectured that the Achæmenid kingdom of Persis and Susiana had already annexed Khurasan, Bactria, and possibly Transoxania before it overthrew the empire of the Modes.

¹ Gibb, H. A. R., op. cit., p. 92.Google Scholar

² The writer hopes to find a later occasion for discussing the second opportunity, which occurred, in his belief, between the middle of the thirteenth Christian century and A.D. 1513.