Nikon the Metanoeite was a tenth-century Byzantine monk and itinerant preacher known for his missionary work. Born in either Argos or Pontus, he spent twelve years practicing extreme asceticism at the Khrysopetro monastery. His abbot eventually sent him to proselytize, leading him to travel through Asia Minor and later to Crete and the Greek mainland. He earned his nickname, which means "repent," by frequently using the word as a preface to his sermons while attempting to re-establish Christian traditions in regions previously under Muslim rule.