[1] The expression “the first Abā’l-Ḥasan” refers to the seventh Imam, Mūsā b. Jaʿfar al-Kāẓim صلوات الله عليهما, one of whose teknonyms is Abū’l-Ḥasan. He is known as “the first Abā’l-Ḥasan” here and in other contexts in order to distinguish him from his son, ʿAlī al-Riḍā, and his great-grandson, ʿAlī al-Hādī صلوات الله عليهما, who are respectively the second and the third Abū’l-Ḥasan.