depends on (1) the continuity of the chain and (2) the confidence in each reporter. Thus would al-Balâdhuri start his narrative regarding the campaign of the Prophet against Najrân:[1] "Bakr ibn-al-Haitham related to me, that ‘Abdallâh ibn-Ṣâliḥ related to him, on the authority of al-Laith ibn-Sa‘d, on the authority of Yûnus ibn-Ziyâd al-Aili, on the authority of az-Zuhri, who said...."
This form of historic composition is unique in the case of the Arabs and meets the most essential requirements of modern historiography, namely, "back to the source" and "trace the line of authorities." The system, however, has its drawbacks in that it crystallized the record of events and rendered deviation from the trodden path sacrilegious. Aside from the use of judgment in the choice of isnâd—the series of authorities—the Arabian authors exercised very little power of analysis, criticism, comparison or inference, their golden rule being "what has been once well said need not be told again." Aṭ-Ṭabari, in the introduction to his great work, gives expression to that principle, where, conscious of the exception that many of his readers might take to some of his reports, he pleads,[2] "We only transmit to others what has been transmitted to us."
Another way of handling traditions is that in which the compiler combines different traditions into one continuous whole, prefixing a statement of his authorities or contenting himself by interrupting the narrative, wherever need may be, by citing the particular authority. While al-Balâdhuri is an exponent of the former type and spares no pains in basing every fact, whenever possible, on an independent isnâd, yet he sometimes resorts to the other method as he himself acknowledges in the first lines of his Futûḥ (p. 15):
