Gregory Chioniades ( el, Γρηγόριος Χιονιάδης, Grēgorios Chioniadēs; c. 1240 – c. 1320) was a

Byzantine Greek Medieval Greek (also known as Middle Greek, Byzantine Greek, or Romaic) is the stage of the Greek language between the end of classical antiquity in the 5th–6th centuries and the end of the Middle Ages, conventionally dated to the Ottoman c ...

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either ...

. He traveled to

Persia Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...

, where he learned Persian mathematical and astronomical science, which he introduced into

Byzantium Byzantium () or Byzantion ( grc, Βυζάντιον) was an ancient Greek city in classical antiquity that became known as Constantinople in late antiquity and Istanbul today. The Greek name ''Byzantion'' and its Latinization ''Byzantium' ...

upon his return from Persia and founded an astronomical academy at Trebizond. Choniades also served as Orthodox bishop in

Tabriz Tabriz ( fa, تبریز ; ) is a city in northwestern Iran, serving as the capital of East Azerbaijan Province. It is the sixth-most-populous city in Iran. In the Quru River valley in Iran's historic Azerbaijan region between long ridges of vo ...

Biography

Information about Chioniades survives from some contemporary sources. In 1347, George Chrysokokkes wrote that He was born in Constantinople, probably around 1240, and was originally named George. Sixteen of Chioniades' letters have survived, which confirm that he received assistance from Alexios II and traveled to Persia. Chioniades translated a number of

Arabic Arabic (, ' ; , ' or ) is a Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C. E.Watson; Walter ...

and Persian works on

mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...

and

astronomy Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, g ...

, including the astronomical tables of his teacher Shams al-Din al-Bukhari, who had worked at the famous

Maragheh observatory The Maragheh observatory (Persian: رصدخانه مراغه), also spelled Maragha, Maragah, Marageh, and Maraga, was an astronomical observatory established in the mid 13th century under the patronage of the Ilkhanid Hulagu and the directorship ...

under the polymath

Nasir al-Din al-Tusi Muhammad ibn Muhammad ibn al-Hasan al-Tūsī ( fa, محمد ابن محمد ابن حسن طوسی 18 February 1201 – 26 June 1274), better known as Nasir al-Din al-Tusi ( fa, نصیر الدین طوسی, links=no; or simply Tusi in the West ...

. Chioniades played an important role in transmitting several innovations from the Islamic world to Europe. These include the introduction of the universal latitude-independent

astrolabe An astrolabe ( grc, ἀστρολάβος ; ar, ٱلأَسْطُرلاب ; persian, ستاره‌یاب ) is an ancient astronomical instrument that was a handheld model of the universe. Its various functions also make it an elaborate inclin ...

to Europe and a Greek description of the

Tusi couple The Tusi couple is a mathematical device in which a small circle rotates inside a larger circle twice the diameter of the smaller circle. Rotations of the circles cause a point on the circumference of the smaller circle to oscillate back and fo ...

, which would later have an influence on

Copernican heliocentrism Copernican heliocentrism is the astronomical model developed by Nicolaus Copernicus and published in 1543. This model positioned the Sun at the center of the Universe, motionless, with Earth and the other planets orbiting around it in circular ...

. Chioniades also translated several '' Zij'' treatises into Greek, including the Persian '' Zij-i Ilkhani'' by al-Tusi and the Maragheh observatory as well as the Seljuk ''Sanjaric Tables'' by al-Khazini, an Islamic astronomer of Byzantine Greek descent. Chioniades resided in Tabriz, at the time the Mongol capital, from 1295 to 1296, serving as the Orthodox bishop to the Orthodox community in that city, and later returned to Constantinople. In 1302 he returned to Tabriz as bishop. According to David Pingree, this may have been in connection with

Andronikos II Palaiologos , image = Andronikos II Palaiologos2.jpg , caption = Miniature from the manuscript of George Pachymeres' ''Historia'' , succession = Byzantine emperor , reign = 11 December 1282 –24 May 1328 , coronation = 8 Novemb ...

's attempt to form an alliance with Ghazan Khan in the summer of 1302. He stayed at Tabriz at least until 1310, before returning to Trebizond, where he is attested as a

hieromonk A hieromonk ( el, Ἱερομόναχος, Ieromonachos; ka, მღვდელმონაზონი, tr; Slavonic: ''Ieromonakh'', ro, Ieromonah), also called a priestmonk, is a monk who is also a priest in the Eastern Orthodox Church an ...

around 1315. Chioniades also wrote religious works, including a commentary on

John of Damascus John of Damascus ( ar, يوحنا الدمشقي, Yūḥanna ad-Dimashqī; gr, Ἰωάννης ὁ Δαμασκηνός, Ioánnēs ho Damaskēnós, ; la, Ioannes Damascenus) or John Damascene was a Christian monk, priest, hymnographer, and ...

, a liturgy on St. Eugenios of Trebizond, and a profrssion of faith.

Notes

Sources

* Fryde, Edmund Boleslaw "The Early

Palaeologan Renaissance The Palaeologan Renaissance or Palaiologan Renaissance is the final period in the development of Byzantine art. It coincided with the reign of the Palaiologoi, the last dynasty to rule the Byzantine Empire (1261–1453), and essentially preceded ...

1261 - C. 1360" 2000 * * * * * * {{DEFAULTSORT:Choniades, Gregory People from Constantinople 13th-century Byzantine monks 14th-century Byzantine monks Byzantine astronomers 13th-century Eastern Orthodox bishops 14th-century Eastern Orthodox bishops 1240s births 1320s deaths Year of birth uncertain Year of death uncertain 13th-century Byzantine scientists 14th-century Byzantine scientists 13th-century Byzantine writers 14th-century Byzantine writers People of the Empire of Trebizond History of Tabriz People of the Ilkhanate Translators to Greek 14th-century Greek writers 14th-century Greek philosophers 14th-century Greek educators 14th-century Greek scientists 13th-century Greek writers 13th-century Greek philosophers 13th-century Greek educators 13th-century Greek scientists 13th-century Greek mathematicians 14th-century Greek mathematicians