Koryun (Կորյուն) was an Armenian historian who lived in Armenia during the 5th century AD. He received his early education under Mesrob Mashtots and continued it in Byzantium. In 432 Koryun returned to Armenia. Later, he was appointed as a Bishop of Georgia.
Koryun was one of the translators of the Bible into the Armenian language. He was the origin of the claim that the Georgian alphabet was created by MesrobMashtots.
After death of Mashtots, Koryun was tasked by HovsepHoghotsmetsi, one of spirtual leaders at that time, to start writing Mesrop's biography. Now his work is known as "VarqMashtotsi" (Life of Mashtots). He finished his work before Avarayr battle in 451 and new political developments in the region. In modern period it was translated in Russian, English, French and Germany.
You can read Koryun's book ( "Varq Mashtotsi", Life of Mashtots) hear http://armenianhouse.org/koryun/mashtots-en.html (copy and past this url)