1. Historical Background

The city of Trebizond had established a tradition in the study of mathematical sciences, especially astronomy, arithmetic and geometry. Already in the 7th century, the renowned teacher Tychikos probably taught there mathematics as well as elements of science;¹ his classes were attended by students from nearby areas and even from Constantinople, possibly at the expense of the Byzantine state. The church of St. Eugenios, where he used to teach, became a centre of attraction for youths from all over the Empire, as reported in the autobiography of one of his students, Ananias of Shirak (from Shirak, Armenia),² who also mentions his teacher’s rich library.

There are no sources providing information about the operation of the school in the 9^th-10^th centuries.³ The systematic development of sciences is attested from the 11^th century on, and especially in the years of the Grand Komnenoi (1204-1461), in the state of Trebizond, when a group of important scholars appeared and organised the School of Trebizond, according to the Byzantine standards of that period: a number of students were gathered around a famous teacher before they followed their own careers as teachers. The school was greatly helped by Emperor Alexios II Grand Komnenos (1297-1330), who paid considerable amounts inviting astronomers, physicians and philosophers to teach.⁴ The school also flourished in the years of Alexios III Grand Komnenos (1349-1390), who supported it in every possible way. Although the school operated until the fall of Trebizond to the Ottomans (1461), limited information is provided by the sources after Alexios III’s death.

2. Structure and Operation

The school was initially based at the church of St. Eugenios, where Tychikos supposedly established his library already in the 7^th century; after the church was destroyed by fire in 1340, the lessons were given at the church of Hagia Sophia (the Divine Wisdom), 2 km to the west of Trebizond.⁵

The function of the school was defined by each renowned scholar who became the pole of attraction and the teacher of higher-level students; this was how schools of higher education opeated at that period. The teacher decided on the content and the structure of the lessons according to his interests.⁶

The School of Trebizond has been associated with influential scholars of the Late Byzantine period. Among those who taught there were Gregory Chioniades, the priest Manuel, Constantine Loukites and Andrew Libadenos, who all systematically studied astronomy and mathematics with spectacular results.⁷ Some of their students were George Chrysokokkes, cardinal Bessarion and Georgios Amiroutzes. The school became the centre of attraction for scholars interested in astronomy from various regions of the Byzantine Empire, as happened with George Akropolites, who visited the city in 1281 sent by Emperor Michael VIII Palaiologos (1261-1282).

3. Impact on sciences

In its heyday, the school is characterized by an intense interest in Persian astronomy, while Trebizond became the point throuhg which Persian astronomical tradition was introduced in Byzantium. This was partly due to the geographical position of the city, the last station in the routes of communication and trade with the East. Apart from commercial relations, the Empire of Trebizond had also close diplomatic ties with Persia. It should be noted that astronomy in that period in Persia was highly developed, as suggested by both written sources and the existence of an observatory in Maraga. Important for the introduction of the Persian astronomy to the School of Trebizond was the role of Gregory Chioniades (late 13^th-early 14^th century): Chioniades travelled to Persia, learned the Persian language, studied astronomy by Shamsh al-Din al-Βukhari, a prominent Persian astronomer, and collected a large number of texts, including notes taken during his teacher’s lectures,⁸ which he later took to Trebizond; they were translated by the priest Manuel and Chioniades used them in his own classes.

A series of astronomical texts of the same period proves the attraction of the school and the increased interest in astronomy including, apart from the translation of the work of Shamsh al‑Din al‑Bukhari, a text of astronomical predictions about the city of Trebizond in 1336.⁹

The scholars gathered in Trebizond also served as mediators as they were responsible for spreading the Persian astronomical tradition to Constantinople and the West. The “Introduction to the Syntaxis of the Persians” written by George Chrysokokkes in 1346 is a work that greatly contributed to the development of Byzantine astronomical studies.