ASĀS (pl. osos), “foundation, basis,” a degree of the Ismaʿili daʿwa hierarchy. It designates the man who discloses the spiritual interpretation (taʾwīl) of the revelation (tanzīl ) and who knows the inner meaning (bāṭen) of the outer (ẓāher) religious law (šarīʿa) and imparts this to the initiates. According to Ismaʿili teaching, each of the six “messenger-prophets” (nāṭeq, pl. noṭaqāʾ) who have hitherto been sent with a šarīʿa has been accompanied by an asās: Ādam by Šīs (or, more rarely, Hābīl); Nūḥ (Noah) by Sām; Ebrāhīm (Abraham) by Esmāʿīl; Mūsā (Moses) by Yūšaʿ b. Nūn (or, more rarely, Hārūn); ʿĪsā (Jesus) by Šemʿūn al-Ṣafā (Simon Peter); Moḥammad by ʿAlī b. Abī Ṭāleb. The 7th nāṭeq, the long awaited Mahdī/Qāʾem, will not have any asās with him; since he will not be bringing a new šarīʿa but rather will reveal the inner meaning of all previous religions. The question of whether Adam revealed a šarīʿa and had an asās was a contentious issue in early Ismaʿilism (cf. Kermānī, Ketāb al-rīāż, ed. A. Tāmer, Beirut, 1960, pp. 176ff.). The term asās is not the original name for this figure in Ismaʿili doctrine; pre- and early Fatimid texts use instead the old Shiʿite term waṣī, “plenipotentiary, envoy, executor” (cf. Manṣūr al-Yaman, Ketāb al-kašf; ed. P. Strothmann, London, 1952, p. 165; Qāżī Noʿmān, Orǰūza, ed. I. Poonawala, Montreal, 1970, pp. 34-37). Not until the Neoplatonic “Persian school” in the early 4th/10th century was the term asās introduced. Nasafī (d. 331/942-43) was probably the first to employ it in his Ketāb al-maḥṣūl, which is now lost; so one concludes from quotations in the Eṣlāḥ of Abū Ḥātem Rāzī (see Madelung, “Imamat,” p. 102 n. 320). Nasafī’s disciple Abū Yaʿqūb Seǰestānī (mid 4th/10th century), who, like his master, denied the šarīʿa and the asās of Adam, still used waṣī and asās as synonyms (Eṯbāt al-nobūwāt, ed. A. Tāmer, Beirut, 1966, p. 187; Ketāb al-noṣra, cited in Kermānī’s Ketāb al-rīāż, pp. 209f.). The Resāla al-moḏheba (ed. A. Tāmer in Ḵams rasāʾel esmāʿīlīya, p. 54) attributed to Qāżī Noʿmān and the Ketāb al-fatarāt (MS. Tübingen Ma VI 297) ascribed to Jaʿfar b. Manṣūr Yaman mark the adoption of the new concept by Fatimid literature in the time of Caliph Moʿezz (r. 341-65/953-75).


See also W. Ivanov, Brief Survey of the Evolution of Ismailism, Bombay, 1952, pp. 57-59.

Idem, Studies in Early Persian Ismailism, Bombay, 1955, pp. 12f., 99-102.

W. Madelung, “Das Imamat in der frühen ismailitischen Lehre,” Der Islam 35. 1961, p. 102.

(H. Halm)

Originally Published: December 15, 1987

Last Updated: August 16, 2011

This article is available in print.
Vol. II, Fasc. 7, p. 705

Cite this entry:

H. Halm, “ASĀS,” Encyclopædia Iranica, II/7, p. 705, available online at (accessed on 30 December 2012).