Iyob of Edessa Job of Edessa, Ayyūb al-Ruhāwī (2nd half of 8th cent. – ca. 835?) [Ch. of E. or Syr. Orth.]

Natural philosopher, translator, and physician, active in Iraq in the first Abbasid cent., nicknamed ‘al-Abrash’, or ‘the Spotted’. The exact dates of his life are not known, but scholars estimate that he lived between 760 and 835. He was active in the time of the Abbasid caliph al-Maʾmūn (r. 813–33). Both Iyob and his son Ibrāhīm worked as physicians in the entourage of the Abbasid family. Iyob was sent by al-Maʾmūn to Khurasan to serve as ʿAbd Allāh b. Ṭāhir’s physician, when the latter became governor there in the early 830s. It seems unlikely that he would have been charged with such a task at the advanced age of 70; his estimated year of birth, probably based solely on Bar ʿEbroyo’s reference to Iyob (Abbeloos and Lamy, Gregorii Barhebraei chronicon ecclesiasticum, vol. 2, 181) as someone living in the era of Patr. Timotheos I, is therefore probably too early. In the same passage, Bar ʿEbroyo calls Iyob a philosopher ‘who followed the doctrine of Nestorius’. Mingana interpreted this as Job having converted from the Melkite or Syr. Orth. to the Ch. of E., probably on account of his Edessene origins. However, historical references to his conversion are lacking, and the possibility should be considered that Bar ʿEbroyo’s claim is based on conjecture. There are no earlier sources that refer to his ecclesiastical affiliation, and the only surviving mss. of his works were produced in a Syr. Orth. milieu.

In his letter to ʿAlī b. Yaḥyā b. al-Munajjim about the translations of Galen’s work into Arabic, Ḥunayn b. Isḥāq (d. 873) mentions Iyob as a translator of 36 of Galen’s works, mostly from Greek into Syriac. He probably translated works by Aristotle and Ptolemy as well. Of his own works only two survive, the most important of which is the ‘Book of Treasures’ (Ktābā d-simātā). It deals with a wide range of natural phenomena which Iyob analyzes according to his theory of the elements. It contains six discourses covering a wide range of disciplines, such as anatomy, zoology, psychology, chemistry, metallurgy, meteorology, and astronomy. Iyob presents explanations for countless aspects of the natural world, with a distinct etiological focus and style that resembles the genre of problemata physica. He begins the work with his theory regarding the four simple and abstract essences, i.e., heat, cold, humidity and dryness, which, if found in individual compositions, constitute essences of a secondary kind. Iyob employs the fact that the primary essences are antagonistic as proof of the existence of God, whose act of creation consisted of bringing these elements together by force, as well as proof of the gradual disintegration of the world that leads to the end of times. The work contains a somewhat covert polemic against Islam, in that it culminates in a refutation of those who believe in an afterlife with physical pleasures. It also reveals Iyob’s acquaintance with contemporary Muʿtazilī thought. The work contains a strong resemblance to the pseudonymous Arabic work ‘The secret of creation’ (Sirr al-khalīqa or Kitāb al-ʿilal), attributed to Apollonius of Tyana (‘Balinus’), which was possibly written in the time of al-Maʾmūn as well, but the relationship between the two has not been thoroughly clarified. Aristotle, Hippocrates, and Galen are directly referenced in Iyob’s work. In addition, scholars claim to have found echoes of the Cappadocian Fathers, Theophrastus, Proclus, and Nemesius of Emesa. However, an in-depth study into Iyobs’s sources remains a desideratum.

Besides the ‘Book of Treasures’, only Iyob’s ‘On Rabies’ survives. The two extant works contain references to titles of some of his works now lost: ‘On Urine’, ‘On the causes of fevers’, ‘On the soul’, ‘On the causes of the coming into existence of the universe from the elements’, ‘On the five senses’, ‘On essences’, ‘On Faith’, and ‘Ten syllogisms taken from the nature of things, which prove that Christ is both God and man’. His work (possibly: works) ‘On Urine’ was known by several Arabic scientists in the centuries to follow, suggesting that it existed in Arabic as well, but it remains impossible to determine whether Iyob authored works in that language. Ullmann (Die Medizin im Islam [1970], 102) supposes that when Abū ʿAbd Allāh al-Khwārizmī, Abū Bakr al-Rāzī and Muṭahhar al-Maqdisī cite Iyob, they are making use of Arabic translations of his Syriac works, while for example Kraus, Mingana, and Ḥabbī assume that Iyob wrote some of his works in Arabic.


  • Y.  Ḥabbī, ‘Ayyūb al-Abraš al-Rahāwī (AD 9/H. 3)’, Majallat al-majmaʿ al-ʿilmī al-ʿIraqī 34 (1983), 124–42.
  • P.  Kraus, Jābir ibn Ḥayyān (2 vols.; 1942–3), vol. 2, 121, 169, 174–5, 274–8.
  • M. Levey, ‘Chemical notions of an early ninth-century Christian encyclopaedist’, Chymia 11 (1966), 29–36.
  • B.  Lewin, ‘Job d’Edesse et son Livre des Trésors’, OrSuec 6 (1957), 21–30.
  • A.  Mingana, Encyclopædia of philosophical and natural sciences as taught in Baghdad about A.D. 817 or Book of treasures by Job of Edessa (1935).
  • G.  Panicker, ‘The Book of Treasures by Mar Job of Edessa’, Harp 8/9 (1995–96), 151–9.
  • G. J.  Reinink, ‘The “Book of Nature” and Syriac apologetics against Islam. The case of Job of Edessa’s Book of Treasures’, in The Book of Nature in the Middle Ages, ed. A. Vanderjagt and K. van Berkel (2005), 71–84.
  • B.  Roggema, ‘Job of Edessa’, in Christian-Muslim relations, ed. Thomas and Roggema, 502–9.
  • J.  Teixidor, Hommage à Baghdad. Traducteurs et lettrés de l’époque ʿabbaside (2007), 58–63.
  • U.  Weisser, Das ‘Buch über das Geheimnis der Schöpfung’ von Pseudo-Apollonios von Tyana (1980), 55–63.

| Iyob of Edessa |


Front Matter A (73) B (53) C (26) D (36) E (27) F (5) G (30) H (22) I (31) J (15) K (11) L (12) M (56) N (19) O (3) P (28) Q (11) R (8) S (71) T (39) U (1) V (5) W (3) X (1) Y (41) Z (4) Back Matter
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