(Νικηφόρος Βρυέννιος), the accomplished husband of Anna Comnena, was born at Orestias in Macedonia in the middle of the eleventh century of the Christian aera. He was the son, or more probably the nephew, of another Nicephorus Bryennius, who is renowned in Byzantine history as one of the first generals of his time, and who, having revolted against the emperor Michael VII. Ducas Parapinaces, assumed the imperial title at Dyrrhachium in 1071. Popular opinion was in favour of the usurper, but he had to contend with a third rival, Nicephorus Botaniates, who was supported by the aristocracy and clergy, and who succeeded in deposing Michael and in becoming recognized as emperor under the name of Nicephorus III. The contest then lay between Nicephorus Betaniates and Nicephorus Bryennius, against whom the former sent an army commanded by Alexis Comnenus, who afterwards became emperor. Bryennius was defeated and made prisoner by Alexis near Calabrya in Thrace : he was treated by the victor with kindness; but Basil, the emperor's minister, ordered his eyes to be put out. His son, or nephew, the subject of this article, escaped the fate of his relative; and no sooner had Alexis Comnenus ascended the throne (1081), than the name of Bryennius became conspicuous as the emperor's most faithful friend.

Bryennius was not only distinguished by bodily beauty and military talents, but also by his learning, the affability of his manners, and the wisdom he shewed in the privy council of the emperor. During the first differences with the crusaders, he was one of the chief supports of the throne; and, in order to reward him for his eminent services, Alexis created for him the dignity of panhypersebastos--a title until then unknown in the code of Byzantine ceremonies, and which gave the bearer the rank of Caesar. But Bryennius is also called Caesar, and we must therefore suppose that this title was formally conferred upon him. The greatest mark of confidence, however, which Alexis bestowed upon him was the hand of his daughter, Anna Comnena, with whom Bryennius lived in happiness during forty years. Bryennius distinguished himself in the war between Alexis and Bohemond, prince of Antioch, and negotiated the peace of 1108 to the entire satisfaction of his sovereign.

Anna Comnena and the empress Irene tried to persuade the emperor to name Bryennius his successor; but Alexis would not deprive his son John of his natural rights. After the death of Alexis in 1118, and the accession of John, Anna and Bryennius conspired against the young emperor, but the conspiracy failed. [ANNA COMNENA.] The cause of its failure was the refusal of Bryennius to act in the decisive moment, for which he was severely blamed by his haughty wife. They were punished with confiscation of their estates and banishment to Oenoe, now Unieh, on the Black Sea, where they led a retired life during several years. Bryennius afterwards recovered the favour of the emperor. In 1137 he went to Cilicia and Syria with the intention of relieving the siege of Antioch by the crusaders; but ill health compelled him to return to Constantinople, where he died soon afterwards.