A Greek from the Peloponnese, he lived the ascetic life for sixty years in the monastery of Dionysiou, and went to his rest in 1605 at the age of eighty-five. It is said of Leontius that he left the monastery only once in all the sixty years: he entered it when he first went to Dionysiou and left it when they carried him out to bury him. He had a miraculous gift of discernment and prophecy, and myrrh flowed from his relics after his death.