A large number of Arabic decrees (ar. sijill, manšūr or marsūm) from the Fatimid, Ayyubid and Mamluk periods have been preserved in Christian, Jewish and Muslim caches. Besides original pieces, dozens of documents that are now lost have survived through copies made in chancery manuals. Although S. M. Stern and more recently Marina Rustow have sought to find continuities between the Fatimid decrees and their Abbasid forerunners, so far there is very little concrete evidence and, above all, no identified decree for the Abbasid period. In this article, Naïm Vanthieghem argues, as both suspected, that this genre indeed had forerunners in the Abbasid period, of which five have survived. Besides a study of their formulary, structure and script, the article tries to reconstruct how they worked and were used and how far this genre spread out through the Empire.