Byzantine statesman, Armenian, brother of Theodora, mother of Emperor Michael III (AD 842-867). Bearer of the highest court title Caesar (καῖσαρ) since 862. He promoted the mission to the Slavs, founded a school for scientific studies in the imperial palace, furthered the elevation of the learned Photius to patriarch. B. was murdered by the parvenu Basilius  I, the founder of the Macedonian dynasty, on 21.4.866.
LMA 1, 1456
ODB 1, 255f.
P. Speck, Die kaiserliche Universität von Konstantinopel, 1974.