Nikephoros Bryennios (Greek: Νικηφόρος Βρυέννιος), Latinized as Nicephorus Bryennius, was an important Byzantine general who was involved in rebellions against the empress Theodora and later the emperor Michael VI Stratiotikos.
Nikephoros Bryennios hailed from Adrianople and by the middle of the 11th century had risen to become the ethnarch responsible for commanding foreign mercenaries in the Macedonian Theme.
[2] In early 1055, as Emperor Constantine IX Monomachos (r. 1042–1055) lay dying, he was persuaded by his councillors, chiefly the logothetes tou dromou John, to pass the throne to the doux of Bulgaria, Nikephoros Proteuon.
[1][5] Returning to the court after Theodora's death, he became embroiled in the military aristocratic unrest surrounding the reign of Michael VI.
[6] Ordered in 1057 to take 3,000 men to reinforce the army at Cappadocia, Nikephoros left the capital in a fit of rage and began plotting to overthrow Michael VI.