Abu Sahl 'Isa ibn Yahya al-Masihi al-Jurjani () was a Christian Persian polymath, physician, and philosopher from ancient Gorgan (, ), who was also active in fields such as astronomy and mathematics.
He wrote an encyclopedic treatise on medicine of one hundred chapters (al-mÃÂ'a fi-l-sanÃÂ'a al-tabi'iyyah; ,), which is one of the earliest Arabic works of its kind and may have been in some respects the model of Avicenna's Qanun.
He wrote other treatises on measles, on the plague, on the pulse, and other subjects.
A number of medieval historians, many of whom were themselves physicians, as well as several modern scholars, have described Abà « Sahl al-Masëḥë as a teacher of Avicenna, or have at least alluded to this widely held view. Avicenna himself, however, in his autobiographical account of his medical studies, does not mention learning medicine from any teacher, stating instead that he mastered the discipline independently within a short period of time.
According to a well-known anecdote reported by NiáºÂÃÂmë ÿArà «á¸Âë () in his ChahÃÂr MaqÃÂla (), Abà « Sahl al-Masëḥë, together with Abà « Naá¹£r Maná¹£à «r ibn ÿIrÃÂq, al-Bërà «në, Avicenna, and Ibn al-KhammÃÂr, were gathered at the court of the Khwarazmshah Maþmà «n ibn Maþmà «n in [Old] Gurganj (, ; present-day Köneürgenç in Turkmenistan, not to be confused with the modern city of Urgench / Gurganj in present-day Uzbekistan). According to NiáºÂÃÂmë, Sultan Maḥmà «d of Ghazni sent an envoy to Maþmà «n requesting that these scholars be dispatched to his court. Maþmà «n conveyed the request to them, stating that he was unable to resist Maḥmà «dâÂÂs demand and that anyone unwilling to go to Ghazni should leave Gurganj without delay.
According to this account, Abà « Sahl al-Masëḥë and Avicenna refused to enter Maḥmà «dâÂÂs service and set out across the Khwarazm desert (Karakum Desert). Avicenna reportedly predicted, on astrological grounds, that they would lose their way, while Abà « Sahl foretold that he would not survive the journey. The two men eventually became lost in the desert; Abà « Sahl died of thirst, whereas Avicenna, after considerable hardship, reached Abivard and later proceeded to Gurgan.
Modern scholarship generally treats this anecdote with caution. While some elements of the account appear to be supported by independent evidenceâÂÂsuch as the documented presence of several of these scholars, including Abà « Sahl al-Masëḥë, at the court of Maþmà «n ibn Maþmà «n, as reflected in works dedicated to the Khwarazmshah and his vizierâ the narrative as a whole cannot be accepted uncritically. In particular, the circumstances surrounding Abà « SahlâÂÂs death remain uncertain. According to Ibn Abë Uá¹£aybiÿa, Avicenna composed a short treatise entitled An epistle to Abà « Sahl al-Masëḥë on angles (R. ilàAbë Sahl al-Masëḥë fë l-zÃÂwiyah, ') after his departure from Gurgan ("Composed at JurjÃÂn",), which may suggest that Abà « Sahl was still alive at that time, or at least calls for caution in accepting the anecdotal chronology in full.