The historical Tabaristan region is in the present-day Mazandaran Province of northern Iran. He was part of a group of astrologers, including Naubakht, Mashallah ibn Athari and Muḥammad ibn Ibrāhīm al-Fazārī, who was asked by Caliph al-Mansur to choose a favorable time for the founding of Baghdad (July 30, 762). The last date in which at-Tabari is mentioned is the month of Shawwal 196 AH (from June 15 to July 13, 812), when he completed The Four Books (commentary to Ptolemy's Tetrabiblos).
^Latham, J.D.; Serjeant, R.B. (2006). Young, M.J.L. (ed.). Religion, learning, and science in the ʻAbbasid period (1 ed.). Cambridge: Cambridge University Press. p. 293. ISBN9780521028875. These Iranian astrologers include Nawbakht, Masha'allah b. Athari al-Basri and Abu Hafs 'Umar b. al-Farrukhan al-Tabari