Polemical writer and bp. The main source for Shemʿun’s life is a much romanticized and not very informative chapter in Yuḥanon of Ephesus ’s ‘Lives of the Eastern Saints’ (ed. Brooks; see Harvey, 97–98). Shemʿun was of Persian origin. There is no evidence that he ever studied at the School of Edessa, even though the School is an important target in his invective. While Yuḥanon presents Shemʿun as bp. (and is followed in this by the later tradition), Beth Arsham, said to be near Seleucia-Ctesiphon , is not otherwise known as an episcopal see, which led Fiey to suggest that Shemʿun was an itinerant bp. and that Beth Arsham was his native town, rather than his diocese (Fiey, 126).

From ca. 500 Shemʿun was active in opposing the spread of dyophysitism in Armenia (where he attended a synod in 505/06; see Garsoïan, 186), in Persia, and in the Byzantine Empire. As a ‘brave warrior on behalf of the true faith’ (Yuḥanon of Ephesus), he often engaged in public debates of high visibility, by which he gained the title ‘Persian debater’ (dorušo parsoyo). At an old age he went to Constantinople, where he met with Yuḥanon of Ephesus and where Empress Theodora (d. 548) paid homage to him, before he died there, probably in the early 540s.

Among Shemʿun’s writings Yuḥanon of Ephesus mentions ‘refutations against heretics’ and ‘many letters on the faith, to many believers everywhere’. Two letters, perhaps three, are preserved. The first is ‘On Barṣawma bp. of Nisibis and the heresy of the Nestorians’ (ed. Assemani with LT; FT in Garsoïan, 450–56; ET in Becker); its specific historical context and date are not known, but it most likely was written during the reign of the Roman Emperor Anastasius (491–518). After having traced the genealogy of (what he saw as) Nestorianism from the Jews in Jesus’ day to Paul of Samosata, Diodore of Tarsus , Theodore of Mopsuestia , Nestorius , Theodoret of Cyrrhus , Hiba of Edessa , and the School of the Persians, he forcefully denounces leaders and scholars of the School, in particular Aqaq , Barṣawma of Nisibis, and Narsai . To these he opposes those who remained faithful to the true faith and rejected Nestorianism and any mention of ‘two Sons, one by nature and one by adoption’. The second letter deals with the persecution of Christians in the city of Nagran (the date of which is disputed: either 518 or 523). Shemʿun’s letter was written from Ḥirta in 524 (ed. Guidi). Although it focuses on the events of the persecution, it also contains polemical notes against both Nestorians and Chalcedonians. I. Shahîd, who discovered and edited a different letter on the same topic, argued for Shemʿun’s authorship of this new letter as well (which is anonymous). In addition, he suggested that Shemʿun is also the author of ‘Book of the Ḥimyarites’ (see Ḥimyar ), which is only fragmentarily known (ed. A. Moberg) and which deals with the same persecution. These two attributions, however, have not been widely accepted.