A Responsum by the Fifth/Eleventh-Century Imāmī Theologian Abū Yaʿlā Muḥammad b. al-Ḥasan b. Ḥamza al-Jaʿfarī on the Number of the Imams

MS Tehran, Dānishgāh-i Tihrān 5396, a multitext codex dating to the eleventh/seventeenth century, includes a tract entitled Risālat al-ḥujja fī l-imāma by the little-known fifth/eleventh-century Imāmī theologian Abū Yaʿlā Muḥammad b. al-Ḥasan b. Ḥamza al-Jaʿfarī. The text is transmitted in two additional witnesses, and in both it is attributed to al-Sharīf al-Murtaḍā (d. 436/1044). The tract was recently published as a work by al-Murtaḍā on the basis of one of these witnesses, which was believed to be a unique copy. The present study discusses the scarce available data about Abū Yaʿlā al-Jaʿfarī and shows that he, rather than al-Murtaḍā, is the author of the tract, which circulated under titles such as Risālat al-ḥujja fī l-imāma and Masʾala fī bayān imāmat al-a ʾimma al-ithnay ʿashar ʿalayhim ṣalawāt Allāh wa-l-malāʾika wal- bashar. Finally, we present a critical edition of the tract, one of the earliest extant Imāmī writings on the question of the number of the imams, on the basis of all three witnesses.