Nikephoros (Greek: Νικηφόρος), also Latinized as Nicephorus or Nicephoros, was the second son of Byzantine emperor Constantine V (reigned 741–775) and Caesar of the Byzantine Empire. He was engaged in a plot against his half-brother, Leo IV (r. 775–780), which cost Nikephoros his title, and was the focal point of numerous usurpation plots during the subsequent reigns of his nephew, Constantine VI (r. 780–797), and of Constantine's mother, Irene of Athens (r. 797–802). He was therefore blinded and exiled to a monastery for most of his life, probably dying in the island of Aphousia sometime after 812.