, Abu ’l-Ḳāsim ʿUbaid Allāh b. ʿAbd Allāh, an important geographer of Persian descent who was apparently born in the early years of the iii^rd century a. h. (c. 820). His grandfather had been a convert to Islām; his father had filled the high office of governor of Ṭabaristān. Little too is known of his own career; he held the important office of controller of the post and intelligence service (Ṣāḥib al-Barīd wa ’l-Ḵh̲abar) in al-Ḏj̲abal (Media); when and how he got this office cannot be ascertained. The Caliph al-Muʿtamid made an intimate friend of him; al-Masʿūdī giv…