Al-Muayyad fid-din Abu Nasr Hibatullah bin Abi Imran Musa bin Daud ash-Shirazi was an outstanding dai, orator, prolific writer, poet and politician. He was born in 390/1000 at Shiraz. His father, tracing his link from a Daylami Ismaili family was also a dai with some influence in the Buwahid orbits of Fars. In one of poems he narrates in his "Diwan al-Muayyad" (poem no. 4) that, "I wish I should get a chance to offer my life as a sacrifice for you, O my Lord. My forefathers and myself have been living in comforts under your patronage and we have never swerved an inch from our devotion to you."
In 429/1037, when al-Muayyad was 39 years old, he received quick promotions in his service as a chief dai of Shiraz and then the hujjat for the whole Iran. He joined the service of the Buwahid Abu Kalijar al-Marzuban (d. 440/1048) at Shiraz. He soon converted Abu Kalijar and many of his Daylami troops. It resulted in court intrigues and a harsh Sunni reaction against him. The Abbasids also insisted on his exile from Iran. Al-Muayyad was therefore obliged to migrate from Shiraz in 438/1046 and reached Cairo next year. He came into the contact of the chief dai al-Kassim bin Abdul Aziz bin Muhammad bin Noman, the great-grandson of Qadi Noman. He had his first audience with al- Mustansir in Cairo a few months later in Shaban, 439/February, 1048. He also procured his close ties with vizir Yazuri, who entrusted him with a section of the Fatimid chancery (diwan al-insha) in 440/1048. He gives the following description of his visit to the Imam in "as-Sirat al-Muayyadiyah" that, "I was taken near the place wherefrom I saw the bright light of the Prophethood. My eyes were dazzled by the light. I shed tears of joy and felt as if I was looking at the face of the Prophet of God and of the Commander of the Faithful, Ali. I prostrated myself before the one who is the fittest person to bow to. I wanted to say something but I was awe-struck."
Al-Mustansir deputed him in 447/1055 on a mission to the Syrian amirs, and notably to Abu Harith al-Basasari with an army of 3000 Arab troops. Al-Muayyad wrote an impassioned qasida on the occasion of the Fatimid occupation of Baghdad. He returned to Cairo in 449/1058, shortly before al-Basasari finally captured Baghdad and had the Fatimid khutba recited.
Al-Muayyad's status before al-Mustansir was as high as that of Salman al-Fars before the Prophet Muhammad. In one of his poems he says:-
law kuntu asartu al-nabiyyi Muhammadan ma kuntu uqassiru an mada Salmanihi wa la qala anta min ahl-i-baiti mu'linan qawlan yakshifu an wuduhi bayanihi"Had I lived in the days of the Prophet, my position before him would have been, in no way less important than that of Salman. He would have said to me in unequivocal terms, you are a member of my family" (Ibid. poem no. 38).
He was elevated as the head of the mission, Bab al-Abwab in 450/1058, and later the supervisor of Dar al-Hikmah in 454/1062. He lodged in the chamber of Dar al-Hikmah and directed the affairs of the Fatimid mission, and was in close contact with the dais as far as in Yamen and India. The learned divines of his time who had left behind the treasures of their masterly works on Ismailism were his pupils. Even the great genius of the type of Nasir Khusaro and Hasan bin Sabbah were his pupils. Nasir Khusaro speaks of al-Muayyad in the following words:- "O Nasir, God has opened a new world of wisdom for you through the teaching of Khwaja al-Muayyad. When he stood on the pulpit to deliver his sermon to the people, intellect was ashamed of its insignificance. He turned my dark nights into bright days by his illuminating arguments. I picked up a particle from his vast wealth of knowledge and I found the revolving heaven under my feet. He showed me in myself both the worlds visible and invisible. I saw the guardian of paradise who said to me, Lo, I am the pupil of al- Muayyad." (vide "Diwan", ed. Nasrullah Taqavi, Tehran, 1928, p. 313)
He also regularly gave lectures at Dar al-Hikmah. The "Majalis" of al-Muayyad, comprised of 8 volumes of one hundred lectures, deal with various theological and philosophical questions, reflecting high watermark of the Ismaili thoughts. He died in 470/1078 at Cairo and was interred inside Dar al-Hikmah, where he resided. Al-Mustansir himself led the funeral rites.