At any rate, not much is known about the early career of Buzurg-Umīd, who was one of the most important Nizārī dāʿīs in Persia. Doubtless, he must have been one of the earliest companions of Ḥasan-i Ṣabbāḥ, working closely with him from the time of Ḥasan’s seizure of the fortress of Alamūt in 483/1090, which marked the foundation of what was to become the Nizārī Ismaili state of Persia. Thus, Buzurg-Umīd collaborated with Ḥasan from early on in spreading the daʿwa throughout the region of Daylam. Juwaynī, Rashīd al-Dīn and Kāshānī, who are our most important primary sources…