DEZKŪH (or Šāhdez), a medieval mountain fortress situated in central Persia on the summit of Mount Ṣoffa, about 8 km south of Isfahan. No information is available on the construction date of this strategically situated fortress, which guarded the routes to Isfahan, but, like some other ruins in the same region, it may have been built as early as the Sasanian period (Minasian, pp. 17-18, 20, 61-62, pls. 1-45). Ebn al-Aṯīr attributed (X, pp. 109-10) the construction of this fortress, which he called the “fortress (qalʿa ) of Isfahan,” to the Saljuq sultan Malekšāh (465-85/1072-92), but this attribution does not seem reliable. It is more likely that Malekšāh merely rebuilt the fortress as a major military outpost of Isfahan, the chief Saljuq capital; it was from his time that the fortress became more generally designated as Šāhdez, reflecting his reconstruction of the existing Dezkūh (Ẓahīr-al-Dīn, p. 40; Rāvandī, p. 156).

The historical importance of Dezkūh is particularly related to the activities of the Nezārī Ismaʿilis in Persia during the early Alamūt period (487-654/1094-1256). Ismaʿili dāʿīs (missionaries) had been active in the region of Isfahan during the11th century, and by the 460s/1170s ʿAbd-al-Malek b. ʿAṭṭāš, the chief dāʿī of Persia and Iraq at the time, had established his headquarters at Isfahan. Ḥasan Ṣabbāḥ’s seizure of Alamūt in 483/1090, which marked the effective foundation of the Nezārī state in Persia, further encouraged the daʿwa, or missionary activities, of Aḥmad b. ʿAbd-al-Malek b. ʿAṭṭāš, who had succeeded his father as dāʿī of Isfahan. Aḥmad, posing as a schoolmaster, gradually succeeded in converting the garrison of Dezkūh, comprised mostly of Deylamī soldiers with Shiʿite tendencies. By 494/1100, or possibly a few years earlier, Aḥmad had gained possession of Dezkūh, which he fortified like other Nezārī mountain castles in Persia (Ẓahīr-al-Dīn, pp. 40-41; Rāvandī, pp. 155 ff.; Rašīd-al-Dīn, 1338 Š./1959, p. 120; idem, 1960, pp. 69-74; Kāšānī, p. 156; Mīrkᵛānd, Tehran, IV, pp. 306 ff.; Hodgson, pp. 85-86; Daftary, pp. 354-55).

The Nezārī capture of Dezkūh was a serious blow to the Saljuqs, especially as soon afterward Aḥmad b. ʿAbd-al-Malek began to collect taxes in the districts around the fortress. Accordingly, the chief focus of the anti-Nezārī campaign conducted by Sultan Moḥammad b. Malekšāh (498-511/1105-18) was Dezkūh. The sultan with a large force besieged the fortress in 500/1107, but the tactics of Aḥmad, who involved the Sunnite ʿolamāʾ of Isfahan in a long religious disputation, in which he argued that the Ismaʿilis were also true Muslims, delayed the conquest for almost a year, until the ʿolamāʾ had rendered their judgment. Eventually battle was joined; Aḥmad and his small band of Nezārīs fought the Saljuqs gallantly from tower to tower. In the final assault most of the Nezārī defenders of Dezkūh were killed; Aḥmad was captured and later executed in Isfahan (Ẓahīr-al-Dīn, pp. 41-42; Rāvandī, pp. 158-161; Bondārī, pp. 90-91; Ebn al-Aṯīr, X, pp. 151-52; Ebn al-Qalānesī, pp. 151-56, containing the text of the victory statement issued on the occasion; Rašīd-al-Dīn, 1338 Š./1959, pp. 121-22; Kāšānī, pp. 156-57; Hodgson, pp. 95-96; Lewis, pp. 53-55; Daftary, pp. 361-62). The conquest of Dezkūh is celebrated in one of the versions of the introduction to the Bahman-nāma (Storey-de Blois, V, 564-65).

Dezkūh was demolished soon after on the sultan’s orders, as he feared its recapture by the Nezārīs. The extensive ruins have been investigated and described by Caro O. Minasian (1897-1972), who was evidently the first person to identify and study the site in modern times (pp. 21-39, 52-54).



(For cited works not given in detail, see “Short References.”) Fatḥ b. ʿAlī Bondārī, Zobdat al-nosÂra wa noḵbat al-ʿeṣra, in Houtsma, Recueil II. F. Daftary, The Ismāʿīlīs. Their History and Doctrines, Cambridge, 1990.

Ebn al-Aṯīr, al-Kāmel fi’l-tārīḵ X, Cairo, 1303/1885.

Ebn al-Qalānesī, Ḏayl tʾarīḵ Demašq, ed. H. F. Amedroz, Leiden, 1908.

M. G. S. Hodgson, The Order of Assassins, the Hague, 1955.

Honarfar, Eṣfahān, pp. 63 ff.

Abu’l-Qāsem ʿAbd-Allāh Kāšānī, Zobdat al-tawārīḵ. Baḵš-e Fāṭemīān wa Nezārīān, ed. M.-T. Dānešpažūh, 2nd ed., Tehran, 1366 Š./1987.

B. Lewis, The Assassins. A Radical Sect in Islam, London, 1967.

M. Mehryār, “Šāhdez kojā’st?” Našrīya-ye Dāneškada-ye Adabīyāt-e EsÂfahān 1, 1343 Š./1964, pp. 87-157.

C. O. Minasian, Shah Diz of Ismaʿili Fame. Its Siege and Destruction, London, 1971.

Rašīd-al-Dīn Fażl-Allāh, Jāmeʿ al-tawārīḵ. Qesmat-e Esmāʿīlīān, ed. M.-T. Dānešpažūh and M. Modarresī Zanjānī, Tehran, 1338 Š./1959.

Idem, Jāmeʿ al-tawārīḵ. Tārīḵ-e Āl-e Saljūq, ed. A. Ateş, Ankara, 1960.

Moḥammad b. ʿAlī Rāvandī, Rāḥat al-sÂodūr wa āyat al-sorūr, ed. M. Eqbāl, London, 1921.

Ẓahīr-al-Dīn Nīšāpūrī, Saljūq-nāma, Tehran, 1332 Š/1953.

(Farhad Daftary)

Originally Published: December 15, 1995

Last Updated: November 22, 2011

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