The Arabic Sources.
The early Arabic sources are remarkably rich in material for the reconstruction of the conquests in Khurāsān and Transoxania. For the earlier period the narratives of Yaʿqūbī and Balādhurī are nearly as full as those of Tabarī, but the special value of the latter lies in his method of compilation which renders the traditions amenable to critical study and thus provides a control for all the others. Moreover, while the other historians, regarding the conquests of Qutayba as definitely completing the reduction of Transoxania, provide only meagre notices for the later period, Tabarī more than compensates for their silence by the enormous wealth of detail embodied in the accounts he quotes from Al-Madāʾinī and others of the last thirty years of Umayyad rule. As a general rule, these three historians rely on different authorities, though all use the earlier histories of Al-Madāʾinī and Abū ʿUbayda to some extent. The monograph of Narshakhī (d. 959 A.D.) based on both Arabic and local sources, with some resemblance to Balādhurī, is unfortunately preserved only in a Persian version of two centuries later which has obviously been edited, to what extent is unknown, but which probably represents the original as unsatisfactorily as Balʿamī’s Persian version of Tabarī. Even so it preserves to us some account of the peoples against whom the Arab invaders were matched, and thus does a little to remedy the defects of the other historians in this respect. It may well be doubted, however, whether some of its narratives merit the reliance placed upon them by van Vloten[17]. The much later historian Ibn al-Athīr introduces very little new material, but confines himself for the most part to abridging and re-editing the narratives in Tabarī, with a tendency to follow the more exaggerated accounts. The geographer Ibn Khūrdādhbih gives a list of titles and names, which is, however, too confused to supply any reliable evidence.
Reference has already been made to certain aspects of the conquests in which the Arab historians are misleading. Their information on the Turks and the principalities of Sogdiana can now, fortunately, be supplemented and parts of their narratives controlled from Chinese sources, chiefly through Chavannes’ valuable “Documents sur les Tou-Kiue (Turcs) Occidentaux.” But there are two other facts which also demand attention: one, that the Arabic authorities, as we possess them, and even with all allowance made for their limitations, are by no means exhaustive; i.e., reliance on omissions in the narratives is an unsafe principle of criticism: the other, that by critical study it is possible to distinguish at certain points several lines of tendentious tradition or legend, directed to the interests of national feeling or of some particular tribe or faction, and centred in some cases round specific persons. These may most conveniently be summarised as follows:
1. A Qaysite tradition, centred on the family of Ibn Khāzim:
2. An Azd-Rabīʿa tradition, centred on Muhallab and hostile to Hajjāj. This became the most popular tradition among the Arabs, and is followed by Balādhurī, but opposed by Yaʿqūbī:
3. A Bāhilite tradition, centred on the tribal hero, Qutayba b. Muslim. In general it found little favour but is occasionally quoted somewhat sarcastically by Tabarī.
4. A local Bukhārā tradition, followed by Yaʿqūbī, Balādhurī and Narshakhī. It presents the early conquests under the form of an historical romance, centred on the Queen Khātūn in the part of a national Boadicea. Other local traditions, which are frequently utilised by Tabarī, seem to be much more free from serious exaggeration:
5. The few notices in Dīnawarī follow an entirely divergent and extremely garbled tradition from unknown sources, which may for the most part be neglected:
6. The quotations made by Balādhurī (e.g. 422. 10) from Abū ʿUbayda show the influence of a rewriting of episodes with an anti-Arab bias, directed to the interests of the Shuʿūbīya movement, in which Abū ʿUbayda was a prominent figure[18].