Leo VI was co-Emperor of Rome from 6 January 870 until the death of his father Basil I on 30 July 886, he then ruled as sole Emperor until his death on 11 May 912. Leo VI was very active in codification of Roman law especially in the area of Roman marriage law. His main "contributions" to Church history were the dismissal of St. Photius the Great as Patriarch of Constantinople and instigating the Tetragamy schism.
* The Cambridge Medieval History, Volume IV Part I. Cambridge: University Press, 1966. * Runciman Bart., Steven Sir. The Emperor Romanus Lecapenus and his Reign. Cambridge: University Press, 1929. * Toynbee, Arnold. Constantine Porphyrogenitus and his world. Oxford, 1973.