Zoeb (al-Dhu’ayb) bin Musa al-Wadei al Hamdani (died-10 Moharram ul Haram, 546 AH/ 1151 AD Hooth, Yemen) is the first Dai al-Mutlaq, a position of spiritual authority in Musta‘līIsmailiBohra Islam. He was appointed to the position by Queen Arwa al-Sulayhi of Yemen on 22 Shabanul Karim, 532 AH.
Appointment as Dai al-Mutlaq by Arwa al-Sulayhi
Arwa al-Sulayhi had been named "Hujja" by Ma'ad al-Mustansir Billah, the FatimidImam. Dai was the intermediary between the Imam (whose headquarters were at Cairo and Yemen), and called Dai al-balagh (not having absolute authority). Dai Lamak ibn Malik and his son Dai Yahya ibn Lamak (d. 1126 AD) were the dai of that era. After the death of the twentieth Ismaili imam Al-Amir, his child At-Tayyib Abi l-Qasim, only a few years old, became the twenty-first Imam. As Tayyib was not in a position to run the Ismaili dawah ("mission"), Al-Amir authorised Arwa al-Sulayhi to run it. She empowered Zoeb bin Moosa to manage the dawah in Yemen under instruction of Imam Amir and extend its influence in India. The Dai had become the Dai al-Mutlaq ("dai with absolute authority") and was made independent from political activity. Because of the independence of the dai, the Fatimid dawat could survive even after Arwa al-Sulayhi's Sulayhid dynasty had lost power in Yemen
^http://www.iis.ac.uk/SiteAssets/pdf/sayyida_hurra.pdf, Sayyida Hurra: The Isma'ili Sulayhid Queen of Yemen,Farhad Daftary, page 4, 'having now been appointed as the chief da'i of Yemen. Lamak, designated as da`i al-balagh, henceforth acted as the executive head of the Yemenite da'wa'