Batiniyya in the context of "Zahir (Islam)"

The Brethren of Purity, also known as The Brethren of Sincerity, were a secret society active during the reign of the Buyid dynasty.

Presumably composed of Muslim philosophers centered in the Buyid port city of Basra, the structure of the organization and the identities of its members have never been clear. Their esoteric teachings and philosophy are expounded in an epistolary style in the Encyclopedia of the Brethren of Purity (Rasā'il Ikhwān al-Ṣafā'), a giant compendium of 52 epistles that would greatly influence later encyclopedias. A good deal of Muslim and Western scholarship has been spent on just pinning down the identities of the Brethren and the century in which they were active.

Schools of Islamic theology are various Islamic schools and branches in different schools of thought regarding creed. The main schools of Islamic theology include the extant Mu'tazili, Ash'ari, Maturidi, and Athari schools; the extinct ones include the Qadari, Jahmi, Murji', and Batini schools.

The main schism between Sunni, Shia, and Khariji branches of Islam was initially more political than theological, but theological differences have developed over time throughout the history of Islam.

Ismailism, known historically and among practitioners as Esotericism, is a branch of Shia Islam. Like all Shia, the Ismailis emphasize a distinction between the exoteric (zahir) and esoteric (batin) dimension of Islam, and hold that the esoteric meaning was preserved from corruption by a line of descendants of Muhammad (imams). However, unlike other Shia, the Ismaili are characterized by a unique emphasis on the esoteric that approaches antinomianism.

The Isma'ili (/ˌɪzmɑːˈɪliː/) get their name from their acceptance of Imam Isma'il ibn Jafar as the appointed spiritual successor (imām) to Ja'far al-Sadiq, wherein they differ from the Twelver Shia, who accept Musa al-Kazim, the younger brother of Isma'il, as the true Imām.