In various places in the Aghani, al-Isfahani refers to Yahya b. Muhammad b. Thawaba (from the Al Thawaba) as his grandfather on his mother's side.[38][lower-alpha 9] It is often suggested that the family of Thawaba, being Shi'i,[lower-alpha 10] bequeathed their sectarian inclination to al-Isfahani.[43][lower-alpha 11] However, the identification of the Thawaba family as Shi'is only found in a late source, Yaqut's (574–626/1178–1225) work.[46] Although it is not implausible for the family of Thawaba to have been Shi'i-inclined in one way or another, since many elite families working under the Abbasid caliphate during this period of time indeed allied with Alids or their partisans,[47] there is no evidence that members of the Thawaba family embraced an extreme form of Shi'ism.[48]