Gregory Chioniades

Gregory Chioniades (Greek: Γρηγόριος Χιονιάδης, romanized: Grēgorios Chioniadēs; c. 1240 – c. 1320) was a Byzantine Greek astronomer. He traveled to Persia, where he learned Persian mathematical and astronomical science, which he introduced into Byzantium upon his return from Persia and founded an astronomical academy at Trebizond. Choniades also served as Orthodox bishop in Tabriz.