Imamate in Ismaili doctrine in the context of "Satr (Isma'ilism)"

The Encyclopedia of the Epistles of Purity is an esoteric Shia Islamic text written by the mysterious Brethren of Purity during the Buyid era. Composed of 52 treatises, it had a great influence on later intellectual leading lights of the Muslim world, such as Ibn Arabi, and was transmitted as far abroad within the Muslim world as al-Andalus.

The identity and period of the authors of the Encyclopedia have not been conclusively established, though the work has been mostly linked with Isma'ilism. Idris Imad al-Din, a prominent 15th-century Isma'ili missionary in Yemen, credited the authorship of the encyclopedia to Muhammad al-Taqi, the 9th Isma'ili Imam, who lived in occultation in the era of the Abbasid Caliphate at the beginning of the Islamic Golden Age.

The Fatimid dynasty (Arabic: الفاطميون, romanized: al-Fāṭimiyyūn) was an Arab dynasty that ruled the Fatimid Caliphate, between 909 and 1171 CE. Descended from Fatima and Ali, and adhering to Isma'ili Shi'ism, they held the Isma'ili imamate, and were regarded as the rightful leaders of the Muslim community. The line of Nizari Isma'ili imams, represented today by the Aga Khans, claims descent from a branch of the Fatimids. The Alavi Bohras, predominantly based in Vadodara, also claim descent from the Fatimids.

The Fatimid dynasty emerged as the leaders of the clandestine early Isma'ili missionary movement (da'wa) in the ninth century CE, ostensibly acting on behalf of a hidden imam, implied at the time to be Muhammad ibn Isma'il. The Isma'ili da'wa spread widely across the Islamic world, then ruled by the Abbasid Caliphate. In 899, the future first Fatimid caliph, Abdallah, proclaimed himself to be the expected imam, causing a rift in the Isma'ili da'wa as the Qarmatians, who did not recognize his imamate, split off. In the meantime, Isma'ili agents had managed to conquer large parts of Yemen and Ifriqiya, as well as launch uprisings in Syria and Iraq. Fleeing Abbasid persecution to Ifriqiya, Abdallah proclaimed himself openly and established the Fatimid Caliphate in 909. From there, the Fatimid imam–caliphs extended their rule over most of the Maghreb as well as Sicily, before conquering Egypt in 969. Founding Cairo as their new capital, for the next two centuries, the Fatimids would be based in Egypt and identified with the country. At their height, the Fatimids claimed control or suzerainty over much of North Africa, Sicily, Egypt, the Levant, the Hejaz, Yemen, and Multan.

Abū Muḥammad ʿAbd Allāh ibn al-Ḥusayn (Arabic: أبو محمد عبد الله بن الحسين; 31 July 874 – 4 March 934), better known by his regnal name al-Mahdī biʾllāh (Arabic: المهدي بالله, "The Rightly Guided by God"), was the founder of the Isma'ili Fatimid Caliphate, the only major Shi'a caliphate in Islamic history, and the eleventh Imam of the Isma'ili branch of Shi'ism.

He was born as Saʿīd ibn al-Ḥusayn (سعيد بن الحسين) in Askar Mukram to a family that led the secret Isma'ili missionary network (da'wa), propagating on behalf of the hidden imam, Muhammad ibn Isma'il, who would return as the prophesied Islamic messiah (mahdi). Orphaned at a young age, he moved to Salamiya, the family's base of operations, where he was adopted by his uncle. In the mid-890s Sa'id succeeded to the leadership of the expanding da'wa, which had expanded and gained adherents across the then Muslim world. However, his claims of not merely being a trustee of the hidden imam, but of him and his ancestors holding the imamate itself, led in 899 to a schism in the Isma'ili movement: those who did not recognise his claims split off to become the Qarmatians. The schism was followed by uprisings of pro-Isma'ili Bedouin in Syria in 902–903, launched without his consent by over-eager supporters, who aimed to force him to come forward as the mahdi. The Bedouin uprising was suppressed by the Abbasids, but drew the attention of the Abbasid Caliphate's authorities to him, forcing him to abandon Salamiya, and flee first to Ramla, then Fustat in Egypt, and finally Sijilmasa in what is now Morocco. There he remained, living as a merchant, until one of his missionaries, Abu Abdallah al-Shi'i, at the head of the Kutama Berbers overthrew the Aghlabid dynasty of Ifriqiya in 909.

Nizari Isma'ilis (Arabic: النزارية, romanized: al-Nizāriyya) are the largest segment of the Ismailis, who are the second-largest branch of Shia Islam after the Twelvers. Nizari teachings emphasise the independent legal jurisprudence or ijtihad—though they reject legal reasoning, or usul—pluralism (the acceptance of racial, ethnic, cultural and inter-religious differences) and social justice. Nizaris, along with Twelvers, adhere to the Jaʽfari school of jurisprudence. The Aga Khan, currently Aga Khan V, is the spiritual leader and Imam of the Nizaris. The global seat of the Ismaili Imamate is in Lisbon, Portugal.

Abū Muḥammad ʿAbd Allāh ibn Yūsuf ibn al-Ḥāfiẓ (Arabic: أبو محمد عبد الله بن يوسف بن الحافظ‎; 1151–1171), better known by his regnal name al-ʿĀḍid li-Dīn Allāh (Arabic: العاضد لدين الله, lit. 'Strengthener of God's Faith'), was the fourteenth and last caliph of the Fatimid dynasty, and the twenty-fourth imam of the Hafizi Isma'ili branch of Shi'a Islam, reigning from 1160 to 1171.

Like his two immediate predecessors, al-Adid came to the throne as a child, and spent his reign as a puppet of various strongmen who occupied the vizierate. He was a mostly helpless bystander to the slow collapse of the Fatimid Caliphate. Tala'i ibn Ruzzik, the vizier who had raised al-Adid to the throne, fell victim to a palace plot in 1161, and was replaced by his son, Ruzzik ibn Tala'i. Ruzzik was in turn overthrown by Shawar in 1163, but the latter lasted only a few months in office before being overthrown by Dirgham. The constant power struggles in Cairo enfeebled the Fatimid state, allowing both the Crusader Kingdom of Jerusalem and the Sunni ruler of Syria, Nur al-Din, to advance their own designs on the country. The Crusaders repeatedly invaded Egypt, extracting tribute and ultimately aiming to conquer it; in turn, Nur al-Din supported Shawar's bid to retake the vizierate from Dirgham, and sent his general Shirkuh to counter the Crusaders. For a while, Shawar played the Crusaders and Syrians against one another, but in January 1169, Shirkuh overthrew Shawar, occupied Cairo and became vizier. When Shirkuh died shortly after, he was succeeded by his nephew, Saladin.

Abu al-Husayn Ahmad ibn Abd Allah ibn Muhammad ibn Isma'il (Arabic: أَبُو ٱلْحُسَيْن أَحْمَد ٱبْن عَبْد ٱللَّٰه ٱبْن مُحَمَّد ٱبْن إسْماعِيل, romanized: Abū al-Ḥusayn Aḥmad ibn ʿAbd Allāh ibn Muḥammad ibn Ismāʿīl; c. 790–840), commonly known as Muhammad al-Taqi (Arabic: مُحَمَّد ٱلْتَقِيّ, romanized: Muḥammad al-Taqī, lit. 'Muhammad the Pious'), was a descendant of the Islamic prophet Muhammad and the ninth of the Isma'ili Imams, succeeding his father, Ahmad al-Wafi (d. 828). Like his father, he lived primarily in Salamiyah, and Abd Allah ibn Maymun al-Qaddah, the chief missionary (da'i), continued to serve as the hijab (lit. 'cover') for him. Known by the title Ṣāḥib al-Rasāʾil (lit. 'lord of the epistles'), al-Taqi is said to have prepared with his followers an encyclopedic text called the Encyclopedia of the Brethren of Purity (Rasāʾil Ikhwān al-Ṣafā). He died in 840 in Salamiyah and was succeeded by his son al-Husayn.

With the death of Ja'far al-Sadiq in 148/765, Isma'il (d. 158/775) and Muhammad (d. 197/813), the gravity of persecutions of the Abbasids had considerably increased. The Isma'ili Imams were impelled to thicken their hiding, therefore, the first dawr al-satr came into force from 197/813 to 268/882, wherein the Imams were known as al-a'imma al-masturin (lit. 'the concealed Imams'). The concealment ended with the establishment of the Fatimid Caliphate (r. 909–1171).

This is a list of the Imams as recognised by the different sub-sects of the Ismai'li sect of Shia Islam. Imams are considered members of the Bayt (Household) of Muhammad through his daughter Fatima.

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.