|Country||Byzantine Empire, Empire of Trebizond|
|Founder||Manuel Erotikos Komnenos|
|Titles||Byzantine Emperor, Emperor of Trebizond, Queen consort of Jerusalem*, Princess of Antioch*, Duchess of Athens*, Despot of Epirus¹ (*By marriage)|
|Dissolution||1185 (Byzantine rule), 1461 (Trapezuntine rule)|
|Cadet branches||Komnenos Doukas¹|
Komnenos (Greek: Κομνηνός), Latinized Comnenus, plural Komnenoi or Comneni (Κομνηνοί [komniˈni]), is a noble family who ruled the Byzantine Empire from 1081 to 1185, and later, as the Grand Komnenoi (Μεγαλοκομνηνοί, Megalokomnenoi) founded and ruled the Empire of Trebizond (1204–1461). Through intermarriages with other noble families, notably the Doukai, Angeloi, and Palaiologoi, the Komnenos name appears among most of the major noble houses of the late Byzantine world.
Michael Psellos reports that the family originated from the village of Komne in Thrace—usually identified with the "Fields of Komnene" (Κομνηνῆς λειμῶνας) mentioned in the 14th century by John Kantakouzenos—a view commonly accepted by modern scholarship. The first known member of the family, Manuel Erotikos Komnenos, acquired extensive estates at Kastamon in Paphlagonia, which became the stronghold of the family in the 11th century. The family thereby quickly became associated with the powerful and prestigious military aristocracy (dynatoi) of Asia Minor, so that despite its Thracian origins it came to be considered "eastern".
The 17th-century scholar Du Cange suggested that the family descended from a Roman noble family that followed Constantine the Great to Constantinople, but although such mythical genealogies were common—and are indeed attested for the closely related Doukas clan—the complete absence of any such assertion in the Byzantine sources argues against Du Cange's view. The Romanian historian George Murnu suggested in 1924 that the Komnenoi were of Aromanian descent, but this view too is now rejected. Modern scholars consider the family to have been entirely of Greek origin.
Isaac I Komnenos, a Stratopedarch of the East under Michael VI, founded the Komnenos dynasty of Byzantine emperors. In 1057 Isaac led a coup against Michael and was proclaimed emperor. Although his reign lasted only till 1059, when his courtiers pressured him to abdicate and become a monk, Isaac initiated many useful reforms. The dynasty returned to the throne with the accession of Alexios I Komnenos, Isaac I's nephew, in 1081. By this time, descendants of all the previous dynasties of Byzantium seem to have disappeared from the realm, such as the important Scleros and Argyros families. Descendants of those emperors lived abroad, having married into the royal families of Georgia, Russia, France, Persia, Italy, Germany, Poland, Bulgaria, Hungary and Serbia; this made it easier for the Komnenos family to ascend to the throne.
Upon their rise to the throne, the Komnenoi became intermarried with the previous Doukas dynasty: Alexios I married Irene Doukaina, the grandniece of Constantine X Doukas, who had succeeded Isaac I in 1059. Thereafter the combined clan often was referred as "Komnenodoukai" (Latinized "Comnenoducae") and several individuals used both surnames together. Several families descended from the Komnenodoukai, such as Palaiologos, Angelos, Vatatzes and Laskaris. Alexios and Irene's youngest daughter Theodora ensured the future success of the Angelos family by marrying into it: Theodora's grandsons became the emperors Isaac II Angelos (reigned 1185–1195 and 1203–1204) and Alexios III Angelos (reigned 1195-1203).
Under Alexios I and his successors the Empire was fairly prosperous and stable. Alexios moved the imperial palace to the Blachernae section of Constantinople. Much of Anatolia was recovered from the Seljuk Turks, who had captured it just prior to Alexios' reign. Alexios also saw the First Crusade pass through Byzantine territory, leading to the establishment of the Crusader states in the east. The Komnenos dynasty was very much involved in crusader affairs, and also intermarried with the reigning families of the Principality of Antioch and the Kingdom of Jerusalem - Theodora Komnene, niece of Manuel I Komnenos, married Baldwin III of Jerusalem, and Maria, grandniece of Manuel, married Amalric I of Jerusalem.
Remarkably, Alexios ruled for 37 years, and his son John II ruled for 25, after uncovering a conspiracy against him by his sister, the chronicler Anna Komnene, and her husband Nikephoros Bryennios. John's son Manuel ruled for another 37 years.
The Komnenos dynasty produced a number of branches. As imperial succession was not in a determined order but rather depended on personal power and the wishes of one's predecessor, within a few generations several relatives were able to present themselves as claimants. After Manuel I's reign the Komnenos dynasty fell into conspiracies and plots like many of its predecessors (and the various contenders within the family sought power and often succeeded in overthrowing the preceding kinsman); Alexios II, the first Komnenos to ascend as a minor, ruled for three years and his conqueror and successor Andronikos I ruled for two, overthrown by the Angelos family under Isaac II who was dethroned and blinded by his own brother Alexios III. The Angeloi were overthrown during the Fourth Crusade in 1204, by Alexios Doukas, a relative from the Doukas family.
Several weeks before the occupation of Constantinople by crusaders in 1204, one branch of the Komnenoi fled back to their homelands in Paphlagonia, along the eastern Black Sea and its hinterland in the Pontic Alps, where they established the Empire of Trebizond. Their first 'emperor', named Alexios I, was the grandson of Emperor Andronikos I. These emperors – the "Grand Komnenoi" (Megaloi Komnenoi or Megalokomnenoi) as they were known – ruled in Trebizond for over 250 years, until 1461, when David Komnenos was defeated and executed by the Ottoman sultan Mehmed II. Mehmed himself claimed descent from the Komnenos family via John Tzelepes Komnenos. The Trapezutine branch of the Komnenos dynasty also held the name of Axouchos as descendants of John Axouch, a Byzantine nobleman and minister to the Byzantine Komnenian Dynasty. A princess of the Trebizond branch is said to have been the mother of prince Yahya (born 1585), who reportedly became a Christian yet spent much of his life attempting to gain the Ottoman throne.
Another branch of the family founded the Despotate of Epirus in 1204, under Michael I Komnenos Doukas, great-grandson of Emperor Alexios I. Helena Doukaina Komnene, a child of that branch of the family, married Guy I de la Roche thereby uniting the Komnenos and the de la Roche houses, with Komnenos family members eventually becoming Dukes of Athens.
One renegade member of the family, also named Isaac, established a separate "empire" on Cyprus in 1184, which lasted until 1191, when the island was taken from him by Richard I of England during the Third Crusade.
When the eastern Empire was restored in 1261 at Constantinople, it was ruled by a family closely related to the Komnenoi, the Palaiologos family. The Palaiologoi ruled until the fall of Constantinople to the Ottoman Turks in 1453.
The last descendant of the dynasty is often considered to have been John Komnenos Molyvdos, a distinguished Ottoman Greek scholar and physician, who became metropolitan bishop of Side and Dristra, and died in 1719. His claims to descent from the imperial dynasty of Trebizond, however, are most likely a fabrication.
Irene Angelina, daughter of Isaac II Angelos and a thus a descendant of Alexios I Komnenos, married Philip of Swabia, the King of Germany. From this union many of the royal and aristocratic families of Western Europe can trace a line of descent.