necessitated the study of the life and character of the reporter on whom the authenticity of the report depends. Thus the reporters were classified into classes (ṭabaḳât). The most famous writer of ṭabaḳât was ibn-Sa‘d (d. 230), the secretary of al-Wâḳidi and the compiler of Kitâb aṭ-Ṭabaḳât al-Kabîr.
Campaigns playing an important rôle in the life of Muḥammad and the early caliphs soon began to assert their claim for special attention and were treated in special books. Besides, the necessity of recording and studying the campaigns arose from the fact that in levying a tax (kharâj) on the conquered land, those in authority were first confronted with the task of determining whether it was taken "by peace", "by capitulation", or "by force", and what the terms in each case were. This gave rise to many books on campaigns (maghâzi), one of the oldest of which is al- Wâḳidi's (d. 207/822). Some books were issued treating of the conquest of one city, most of which books have been lost. Given a number of books on the conquest of different cities, the next step would be to compile them into one whole. That step was taken by al-Balâdhuri—the last great historian of Moslem campaigns.
Before the Abbasid period no books on general history were attempted. In the golden age of the Abbasid caliphate and under Persian influence, historiography flourished and developed a new form of composition. The translation of such books as the Pehlevi Khuday-Nama by ibn-al-Muḳaffa‘ into the Arabic Kitâb al-Mulûk, coupled with the fact that the Moslem commonwealth was now richly recruited by Persian converts, made the idea of chronological collocation of events, for which the school of al-Madinah had paved the way, develop to the plan of a complete series of annals. The first to undertake such a history was aṭ-Ṭabari. Thus the historian who at the rise of Islam was a tradition-
