Al-Mustansir Billah in the context of Mustaali

The vizier (Arabic: وزير, romanized: wazīr) was the senior minister of the Fatimid Caliphate for most of the Egyptian period of its existence. Originally it was held by civilian officials who acted as the chief civilian ministers of the caliphs, analogous to the original model established by the Abbasids. When a vizier was not appointed, an "intermediary" (wāsiṭa) was designated instead. The enfeeblement of the caliph's power and the crisis of the Fatimid regime under Caliph al-Mustansir, however, led to the rise of military strongmen, who dominated the post from the 1070s until the caliphate's end. These "viziers of the sword" were also commanders-in-chief of the army who effectively sidelined the caliphs and ruled in their stead, often seizing power from their predecessors. The last vizier, Saladin, abolished the Fatimid Caliphate in 1171 (see Saladin in Egypt).

The Alavi Bohras are a Tayyibi Musta'lavi Isma'ili Shi'i Muslim community from Gujarat, India. In India, during the time of the 18th Fatimid Imam Al-Mustansir Billah around 1093 AD in Egypt, the designated learned people (wulaat) who were sent from Yemen by missionaries (du'aat) under the guidance of the imam established a da'wah in Khambhat (Gujarat, India).

After the division of the Musta'lid community, the Yemenite Da'wah followed their 21st imam, the son of 20th Imam Al-Amir bi-Ahkam Allah in the succession of Fatimid Imams of Egypt, At-Tayyib Abu'l-Qasim as their Imam of seclusion, and the Bohras are the modern descendants of Tayyibi Da'wah established from Khambhat, Patan and Sidhpur in the 5th century Hijri and also the immigrants from Yemeni Tayyibi Da'wah.

Musta'li Isma'ilism (Arabic: المستعلية, romanized: al-Mustaʿliyya) is a branch of Isma'ilism named for their acceptance of al-Musta'li as the legitimate ninth Fatimid caliph and legitimate successor to his father, al-Mustansir Billah (r. 1036–1094/1095). The Nizari the other living branch of Ismailism, led by Aga Khan V believe the ninth caliph was al-Musta'li's elder brother, Nizar.

The Musta'li originated in Fatimid-ruled Egypt, later moved its religious center to Yemen, and gained a foothold in 11th-century Western India through missionaries.

Abu'l-Najm Badr ibn Abdallah al-Jamali al-Mustansiri, better known as Badr al-Jamali (Arabic: بدر الجمالى) or by his eventual title as Amir al-Juyush (أمير الجيوش, lit. 'Commander of the Armies'), was a military commander and statesman for the Fatimid Caliphate under Caliph al-Mustansir. Of Armenian origin but a convert to Islam, Badr had been brought up as a military slave (mamluk) by the ruler of Tripoli, Jamal al-Dawla ibn Ammar. In the 1060s, he was appointed twice as governor of Damascus in Syria, at a time when Fatimid authority there was disintegrating, and the central government in Egypt was on the verge of collapse as a result of the Mustansirite Hardship. Badr was unable to prevent the loss of most of Syria to local potentates and Turkoman warlords, but managed to hold on to the coastal cities, making Acre his base.

As the sole major military commander outside Egypt, he was called upon by al-Mustansir to help rescue the dynasty. Badr landed in Egypt in late 1073, rapidly eliminated his rivals, and was appointed vizier with plenipotentiary powers, making him a quasi-sultan or military dictator, with the caliph relegated to his religious duties as Isma'ili imam. Control over the state was solidified with the marriage of one of his daughters to al-Mustansir, and the appointment of his own son, al-Afdal Shahanshah, as his successor in 1085. Badr managed to restore order in Egypt and initiated major administrative reforms, defeated Turkoman attempts to invade Egypt, and recovered control over Palestine and the Hejaz. He initiated a series of new constructions, including the Juyushi Mosque and the new city wall of Cairo, some of whose gates stand to this day. Badr's tenure saved the Fatimid regime, but also began a period where the vizierate was dominated by military strongmen who held power on their own, rather than through caliphal appointment, and who increasingly sidelined the caliphs to puppet rulers. Badr also initiated a wave of Armenian migration into Egypt, and was the first of a series of viziers of Armenian origin, who played a major role in the fortunes of the Fatimid Caliphate over the subsequent century.