Severus Sebokht of Nisibis flourished in the early-mid 7th century and was bishop of the great convent of Kenneshrin (the "Eagle's nest") at which Greek was studied extensively. He was one of the foremost scientific writers of his time. His works are mainly scientific or philosophical in character, although little has been translated into English.
He is best known today for a remark which shows that what we call today "Arabic" numerals were coming into use.
Material from Wright
Severus Sebokht (d. 666-7 A.D.) 1 of Nisibis 2, bishop of the convent of Ken-neshre, at this time one of the chief seats of Greek learning in western Syria 3 flourished at the same time as Marutha, under the patriarch Athanasius Gammala (died in 631 4) and his successor John.
He devoted himself to philosophical and mathematical as well as theological studies 5. Of the first we have specimens in his treatise on the syllogisms in the Analytica Priora of Aristotle, his commentary on the Περι ερμηνείας, and his letters to the priest Aitilaha of Mosul on certain terms in the Περι ερμηνείας, and to the periodeutes Yaunan or Jonas on some points in the logic of Aristotle 6. Of his astronomical and geographical studies there are a few examples in Brit. Mus. Add. 14538, ff. 153-155 7, such as whether the heaven surrounds the earth in the form of a wheel or sphere, on the habitable and uninhabitable portions of the earth, on the measurement of the heaven and the earth and the space between them, and on the motions of the sun and moon 8. In the Royal Library at Berlin there is a short treatise of his on the astrolabe 9.
More or less theological in their nature are his letter to the priest and periodeutes Basil of Cyprus, on the 14th of Nisan, A. Gr. 976 (665 A.D.) 10, a treatise on the weeks of Daniel 11, and letters to Sergius, abbot of Shiggar (Sinjar), on two discourses of Gregory Nazianzen 12. He is also said to have drawn up a liturgy 13.
- On the Persian name Sebokht see Noldeke, Gesch. des Artachsir i Papakan, in Beitrage z. Kunde d. indogerm. Sprachen, iv. 49, note 4; Geschichte d. Perser und Araber, p. 396, note 1.
- See Wright, Catal., p. 598, col. 1.
- See B.O., ii. 335 ; Bar-Hebraeus, Chron. Eccles., i. 275.
- According to Bar-Hebraeus, Chron. Eccles., i. 275 ; B.O., ii. 334. Dionysius of Tell-Mahre gives 644.
- Compare Renan, De Philos. Peripat. ap. Syros, pp. 29, 30.
- See Brit. Mus. Add. 14660 and 17156 (Wright, Catal., pp. 1160-63), and the Catal. of the Royal Library of Berlin, Sachau 226, 6, 9.
- Wright, Catal., p. 1008.
- See Sachau, Ined. Syr., pp. 127-134.
- Alter Bestand 37, 2 (Kurzes Verzeichniss, p. 32).
- Same MS., 3.
- Wright, Catal., p. 988, col. 2.
- Ibid., p. 432, col. 2.
- B.O., ii. 463.
Material from Sebastian Brock
Severus Sebokht (W' d.666-7). Bishop of the monastery of Qenneshre, and one of the most learned men of his time in the fields of astronomy and philosophy. Several works of his in both these fields survive, notably treatises on the Astrolabe and on the Constellations, letters on points of logic addressed to Aitalaha of Nineveh and to a periodeutes Yaunan, and a treatise on Syllogisms (written in 638). He also translated from Middle Persian a compendium on logic written by Paul the Persian for the Persian shah Khosro I (d. 579).
Material from the internet
He wrote letters on theological subjects to Basil of Cyprus and Sergius, abbot of Skiggar, as well as two discourses on St. Gregory Nazianzen. On Aristotelian logic he composed a treatise on the syllogisms in the Analytics of Aristotle, a commentary on the Hermeneutics which was based on the commentary of Paul the Persian, a letter to Aitilaha of Mosul on certain terms used in the Hermeneutics (Brit. Mus. Add. 17156), and a letter to the periodeutes Yaunan on the logic of Aristotle (Camb. Univ. Lib. Add. 2812).
In addition to these works on logic he also wrote on astronomical subjects (Brit. Mus. Add. 14538), and composed a treatise on the astronomical instrument known as the astrolabe, which has been edited and published by F. Nau (Paris, 1899). In all this he showed himself the product of Alexandrian science and illustrated the widening scientific interests of the period. It seems that he took steps towards introducing the Indian numerals, but this was not carried on by any immediate successor. His work represents the highest level reached by any Syriac scientist and this, it will be noted, was associated with Kennesrin.
In 662AD he wrote concerning the new numerals, which were moving West and were to become what we know as 'Arabic' numerals:
- I will omit all discussion of the science of the Indians, ... , of their subtle discoveries in astronomy, discoveries that are more ingenious than those of the Greeks and the Babylonians, and of their valuable methods of calculation which surpass description. I wish only to say that this computation is done by means of nine signs. If those who believe, because they speak Greek, that they have arrived at the limits of science, would read the Indian texts, they would be convinced, even if a little late in the day, that there are others who know something of value. (Found online: supposed to come from "The Wonder That Was India, A Survey of the Culture of the Indian Sub-Continent Before the Coming of the Muslims", by A.L. Basham, Reader in the History of India in the University of London, Sidgwick and Jackson, London, 1954, repr. 1961).
According to google book search's scan of page 48 of A History of Mathematical Notations, by Florian Cajori (1993):
- The earliest-known reference to Hindu numerals outside of India is the one due to Bishop Severus Sebokht of Nisibus, who, living in the convent of Kenneshre on the Euphrates, refers to them in a fragment of a manuscript (MS Syriac [Paris], No. 346) of the year 662 A.D.
- Like many of his contemporaries, Severus was bicultural, partaking of the Byzantine Greek influence on Western Syrian intellectual circles while fully immersed in his own Syrian cultural milieu. He does, however, criticize the contemporary Greek tendency to assume intellectual superiority and asserts his own capabilities as a native Syrian, raising a strong polemical voice against the cultural hegemony of the Greek-speaking world over that of provincials. A leading figure in the teaching and commentary tradition of Aristotelian philosophy, especially in logic and syllogisms, Severus produced a Discourse on Syllogisms in Prior Analytics (638 CE) and wrote commentaries on other philosophical texts. He translated into Syriac Paul the Persian's commentary on Aristotle's De interpretatione ... He was familiar with Ptolemy's Handy Tables, and there is some indication that he translated the Almagest into Syriac; in any case, he most certainly taught it in the school of Nisbis and then later in Western Syria ...
- Specialized treatments of Severus and his contemporaries appear in S. Brock, "From Antagonism to Assimilation: Syriac Attitudes to Greek Learning" in Syriac Perspectives on Late Antiquity (London: 1984): V, 17-34, esp. 23-4, 28 and in two works by D. Pingree: "The Greek Influence on Early Islamic Mathematical Astronomy," Journal of the American Oriental Society 93 1993: 32-43, esp. 34-5; and "The Teaching of the Almagest in Late Antiquity" in The Sciences in Greco-Roman Society. ed. T. Barnes. (Edmonton: 1994): 73-98, esp. 94-5.
From google book search, in "Aristotelian Meteorology in Syriac: Barhebraeus, Butyrum Sapientiae, Books of Mineralogy ..." By Hidemi Takahashi, p. 325, it states that Severus was familiar with Ptolemy's Handy Tables (see the French translation of "On the Constellations" by Nau , p.240; Nau [1930-1], p.343 (index)), as was Sergius of Reshaina (Sachau  225.17).
- Severus Sebokht, De Constellationibus. Partial edition by Sachau (1870) 127-134; French tr. and partial edition Nau (1930-1). (Hidemi Takahashi, Aristotelian Meteorology in Syriac: Barhebraeus, Butyrum Sapientiae, Books of Mineralogy ..., p.619, via google book search)
- Severus Sebokht on Indian numerals: F. Nau, 'La plus ancienne mention orientale des chiffres indiens', Journal asiatique 10:16 (1910), 225-227.
- On the Constellations: Ms. Paris Syr. 346, for which see F. Nau, in Revue de l’Orient Chrétien 27 (1929/30), 327-410, 28 (1932), 85-100 (Details from Hugoye). Given in an Online bibliography as Nau, F. "La Traité sur les `Constellations' Écrit, en 661, par Sévère Séboht, Évêque de Yennesrin." Revue de l'orient chrétien 3d series 7 (27); 8 (28) (1929; 1932): 327-410; 85-100.
- On the astrolabe: English translation by M. Margoliouth, in R. Gunther, Astrolabes of the World. I, The Eastern Astrolabes (Oxford, 1932), 82-103. Online here
- F. Nau, "Le Traité Sur l’astrolabe de Sévère Sebokht", Journal asiatique, série 9, t. xiii, 1899, P. 238-303. French translation.
- Scott L. Montgomery. Science in Translation: Movements of Knowledge through Cultures and Time. Chicago: University of Chicago Press, 2000. pp. xii + 326 pp. Halftones, ISBN 0-226-53480-4.
- David Pingree's "The Teaching of the Almagest in Late Antiquity" (75-98)in Timothy D. Barnes (ed.), The Sciences in Greco-Roman Society. Aperion: A Journal for Ancient Philosophy and Science 27.4 (December 1994). Edmonton: Academic Printing & Publishing, 1994. Pp. 125. Price unspecified. ISBN 0-920980-60-0 (hb); ISBN 0-920980-61-9 (pb). Article (pp.80-95) on an anonymous commentary on Ptolemy's "Almagest" in the margins of our oldest copy -- the author concludes Severus Sebokht is the author. (From BMCR)
- Biographical Encyclopedia of Astronomers (Dordrecht: Kluwer Academic Press, forthcoming): Articles by John McMahon on Homer, Hesiod, Vergil, Ovid, Theon of Alexandria, Synesius of Cyrene, Dionysius Exiguus, Cassiodorus, and Severus Sebokht