After he had mastered medicine, he wished to study astronomy; he was informed that in order to satisfy his desire, he would have to go to Persia (then under Ilkhanate rule).
He eventually learned all that he wished to know, and returned to Trebizond, bearing away from Persia a number of astronomical texts which he translated into Greek.
These include the introduction of the universal latitude-independent astrolabe to Europe and a Greek description of the Tusi couple, which would later have an influence on Copernican heliocentrism.
According to David Pingree, this may have been in connection with Andronikos II Palaiologos's attempt to form an alliance with Ghazan Khan in the summer of 1302.
[8] Chioniades also wrote religious works, including a commentary on John of Damascus, a liturgy akolouthia on St. Eugenios of Trebizond, and a profession of faith.