Historian
Most of the information about the life of Muḥammad ibn al-Ḥasan Ibn-i Isfandiyār comes from his only known work
Tārīḫ-i Ṭabaristān. He was in some way attached to Ḥusām al-Daulah Ardašīr, who ruled in Māzandarān (a Northern province of Iran) from 567/1171-2 to 602/1205-6.
Tārīḫ-i Ṭabaristān is a Persian translation from an Arabic work on the history of Ṭabaristān. However, Ibn-i Isfandiyār extended the work to include his own times as he supplemented it with an account of Ardašīr, his ancestors and his descendants. The work was further extended to ca. 750/1349 by an anonymous author.