of Abu Khazr Yaghla b. Zaltaf (d.380 H.) who composed his book known as K. Abu Khazr Yaghla b. Zaltaf,256 in reply to questions sent to him from some Ibadhi scholars, after Abu Khazr had settled in Egypt.257

A contemporary and student of Abu Hazm, Abu Nuh Said b. Zanghil also made contributions in this field. His book is known in Ibadhi sources as K. Said b. Zanghil. This book is still lost,258 but from the citations by al-Barradi in his commentary on the poem of Abu Bakr Ahmad b. al-Nazr, Shifau al-haim fi sharhi badi al-Daaim, it appears that Ibn Zanghil's book dealt with the central theological problems such as "What must not remain unknown of the faith" ما لا يسع جهله من الدين The 'Vision', 'Capacity', the 'creation' of the Qur'an, the speech of God,' etc.259 Both scholars, Abu Khazr and Abu Nuh, took an active part in the last attempt at reviving the Ibadhi Imamate in North Africa.260

In later periods further contributions to this field were made. A great attention was paid to speculative theology, and a remarkable number of important works was written. This was largely due to the instigation of the Ibadhi scholar Abu Muhammad Abdullah b. Muhammad b. Bakr (d. 440 H.) originally from Farsattah in Jabal Nufusah. He moved to Ajillu in southern Algeria and formed the Halqah and Azzabah councils.261 He used to encourage his students to study theology. Although there are no complete works of theology ascribed to him, some of his views were included in K. al-Tuhaf by his student Sulaiman b. Yakhalaf. Abu al-Rabi Sulaiman b. Yakhlaf started teaching theology in Jerba where he was studying jurisprudence with Abu Muhammad Wislan. A large number of Ibadhi students, from different parts of Ibadhi countries of North Africa, gathered around him to study theology. It was after the year 450 H. that his students asked him to write a book on theology. After an initial reluctance, he agreed to their wish and allowed them to write down his lectures, which he later edited and approved.262 This work took a form of a detailed book of two volumes, and was known as K. al-Tuhaf.263

Comparing this book with extant earlier works, it is the most comprehensive work, and contains detailed discussions on the following topics.

Part 1. What must not remain unknown of the faith; walayah and baraah; command and prohibition; the speech of God; faith and infidelity (kufr); enjoining good and prohibiting bad; knowledge and ignorance; prophethood and the Message (al-risalah); unknown prohibitions; individual judgement and when it is lawful; proofs for the existence of another world; the 'stages' of the Ibadhi community (masalik al-din); on regarding opponent Muslims as polytheists and evil-doers (fussaq); eternity in Hell; the vision; Ibadhis opinion of the people of al-Nahr; 'divine decree'; 'Names' and 'attributes' of God; God's 'friendship' and 'enmity;' having sexual intercourse in the prohibited parts not