Translator of Greek medical and philosophical texts into Syriac. Most of the little that is known of his life has to be gleaned from a paragraph in Pseudo-Zacharias (Ecclesiastical History, 9:19). He evidently received his education, which included medicine, in Alexandria, and he is regularly designated in the sources as ‘Archiatros (chief doctor) of Reshʿayna’. Towards the end of his life he was sent by Ephrem, Patr. of Antioch (526/8–545) with a letter to Pope Agapetus; it was on the return from this journey that he died suddenly at Constantinople.

Sergios’s considerable literary output combined both original works, and numerous translations from Greek (a detailed list is given by Hugonnard-Roche, La logique, 125–32). The translations fall into three categories:

1. Theological. The corpus of mystical writings attributed to Dionysius the Areopagite (preserved in ms. Sinai Syr. 52, not yet edited apart from extracts). On the basis of a passage in Yawsep Ḥazzaya’s ‘Book of Questions’, Sergios seems also to have been the translator of the unexpurgated version of Evagrius’s ‘Gnostic Chapters’ (ed. A. Guillaumont [PO 29.1; 1985]; see Guillaumont, Les ‘Kephalaia Gnostica’ d’Évagre le Pontique [1962], 215–27).

2. Medicine and astronomy. A considerable number of medical treatises by Galen are enumerated in a famous letter by Ḥunayn b. Isḥāq (d. 873) as having been the work of Sergios, but only a few of these survive (e.g., ed. E. Sachau, Inedita Syriaca [1870], 101–34; the second treatise there has recently been identified by G. Saliba, in Byzantion 65 [1995], 443–4, as in fact being closely based on Paul of Alexandria).

3. Philosophy. Notably among these are the Pseudo-Aristotelian work, ‘On the Universe’, addressed to Alexander the Great (ed. de Lagarde, Analecta Syriaca [1858], 134–58), and a treatise ‘On the causes of the Universe’ (unpublished) which has only recently been identified by D. Miller (in SymSyr VI, 221–33) as a work by Alexander of Aphrodisias that is lost in Greek, and preserved elsewhere only in Arabic (ed. C. Genequand 2001). In an influential monograph of 1852 E. Renan (followed by Baumstark), attributed a number of anonymous translations to Sergios, including those of Porphyry’s ‘Introduction’ to Aristotle’s logical works, and Aristotle’s ‘Categories’; these attributions, however, are now known to be definitely incorrect.

Sergios’s original writings which survive include: 1. a Treatise on the Spiritual Life (ed. P. Sherwood in L’Orient Syrien 5 [1960], 433–59; 6 [1961], 95–115, 121–156, with FT; IT by E. Fiori [2008]); this prefaces his translation of the Dionysian Corpus. It is already cited, though not by name, by Gabriel Qaṭraya in his ‘Commentary on the Liturgy’; 2. a Treatise addressed to Philotheos, on Aristotle’s ‘Categories’ (unpublished; study and partial FT in Hugonnard-Roche, chap. 7); 3. a Treatise addressed to Theodore, ‘On the aim of all Aristotle’s writings’ (unedited; study and FT of Prologue and Book I by Hugonnard-Roche, chap. 8–9); 4. various Scholia on philosophical terms.