 Until some decades ago, the almost universally accepted dating was the one deduced from the testimonies of al-Tawhîdî and ‘Abd al-Jabbâr al-Hamadânî (see above, 1. Authorship). Marquet reconfirmed Dieterici's earlier hypothesis, placing the compilation of the work between 961 and 980 (al-Tawhîdî's testimony is dated 981), but he also brought the date back to 909, depending on the hypothesis of an Ismâ‘îlî affiliation of the authors. Two treatises have given rise to the idea of an Ismâ‘îli interpretation: Epistle 48 On the invitation (da‘wa) to God and Epistle 50 On the kinds of administration. The encyclopedia would therefore be the oldest exposition of the Ismâ‘îli doctrine, and consequently, the “expected event” might have been the proclamation of the Fatimid caliph ‘Abd Allâh al-Mahdî in Ifriqiyya, which happened in that year (Marquet 1981, 95; Marquet 1972, 66). Hamdani summarizes various opinions concerning the dates of the encyclopedia, and establishes that it was composed in its whole between 873 and 909 (Hamdani 1978; Hamdani 1999, 78; Hamdani 2008; Hamdani, Soufan 2019, 15–16; Poonawala sides with Hamdani’s chronology in Baffioni, Poonawala 2017, 307–308). Hamdani also thinks that the Ikhwân awaited the advent of the Fatimids, the Fatimid character of the Rasâ’il not being in question (Hamdani 1979, 62); he configures a precise role of the imâm in this epistle (Hamdani, Soufan 2019, 6). The fourth section, apart from the first and the last treatises, is claimed to be the core around which the first three sections have been composed (Marquet 1998, 5), as well as the culmination of the epistles, which demonstrates the importance of the mystery of prophecy and of imâmate (Marquet 1998, 8–9 and note 21). Also Madelung recently sided with the hypothesis of an Ismâ‘îlism of the Ikhwân al-Safâ’. Recalling that the Ismâ‘îlis of Mashriq, Iraq and Iran did not recognize the claims of ‘Abd Allâh to be the expected imâm, being rather committed to the Qarmat mission, Madelung hypothesizes that the Ismâ‘îlis of Basra recognized as imâm the member of the family who had remained hidden in Khurâsân, the same person who would also become the founder of the secret brotherhood of the Ihwân al-Ṣafâ’ (Madelung in print; but cf. De Smet 2017, 152, note 1). Madelung’s claim that the epistles are “under the auspices of the hidden seventh imam” is rejected by Poonawala, since “Muḥammad b. Ismā‘īl’s name is never mentioned in the Rasā’il” (Baffioni, Poonawala 2017, 303–305, also on the basis of Hamdani’s opinions).