In his Ta’rīkh al-Mawṣil, al-Azdī (d. 945) records the safe-conduct (amān) said to have been written for the surrender of the Abbasid ‘Abd Allāh b. ‘Alī (d. 764) to his nephew, the caliph al-Manṣūr. This text has been overlooked in discussions of early Abbasid history and in studies of the work of Ibn al-Muqaffa‘ (d. c. 756), who is widely credited with its production. This article presents an annotated translation of the amān and considers its transmission, authenticity, attribution and significance. Parallels with epigraphic, documentary and literary sources suggest that it was indeed originally composed in the early Abbasid period and that it conforms to developing conventions for amāns. Thus, it is important evidence for political theory and practice in the mid-eighth-century caliphate. Furthermore, it probably substantially reflects the agreement between the caliph and his uncle and may indeed be the work of Ibn al-Muqaffa‘.