first four centuries were cast. The notes of his scholars grew into bundles, and these into books. Successive editors added fresh traditions professing to be derived through independent channels from Ibn Abbâs, interpolating at the same time other matter of their own. The six editions of his Commentary now extant, are thus full of variations, and even of contradictory interpretations; but they all undoubtedly contain (as Sprenger thinks) much matter that really proceeded from Ibn Abbâs himself. 

There are no other early Commentaries extant: but we know, by the quotations taken from them, that there formerly existed many such. Sprenger gives a list of thirty in the first two centuries. The most ancient grew out of the School collections; and while he thinks it possible that these may have preserved a greater number of early traditions than the Sunna, it is at the same time admitted that they were less critical and trustworthy. Tabari (d. 310) carefully sifted the labours of his predecessors, and preserved what he deemed to be serviceable. A large fragment of his work is in the Library of the Asiatic Society in Calcutta.

All the Commentaries are based on traditions exactly similar to those already described, setting forth the exposition of difficult passages as given by the early leaders of Islam. They contain also detailed narratives of those incidents in the Prophet's life which, as is supposed, gave occasion to special revelations, or are otherwise alluded to in the Coran; and in this lies their service to the Biographer of to-day. The later Commentaries contain nothing historical that is not borrowed from these earlier works. Special schools took up different branches of the subject. The Grammarians busied themselves with the text of the Coran long before Tabari; some wrote treatises on the rare expressions; others on the difficult phrases. Some illustrated the style; some the sense of the darker, and others the rhetoric of the more remarkable passages;, and these grew up side by side with the historical exegesis. The labours of both classes have been made use of by Thalabi (d. 427), the best Commentator now available, and by Baghawi (d. 516), whose work has been lately lithographed at Bombay. By their time the exegesis had become dialectic, and