Saint Theodosius, Metropolitan of Trebizond, was born in the village of Koritsa, near the Kastorian hills. At eighteen years of age he became a monk at Constantinople and went to the Philotheou monastery on Mt. Athos, where he led a strict ascetic life.
He was chosen igumen of the monastery in 1375, and afterwards was made Metropolitan of Trebizond because of the holiness of his life. He persuaded John Alexius Komnenos to build the monastery of Dionysiou on Mt. Athos. After a God-pleasing life, he died in Trebizond in 1392.