|Emperor and Autocrat of the Romans|
|Emperor of the Byzantine Empire|
|Reign||1060–1078 (Junior Emperor)|
|Successor||Nikephoros III Botaneiates|
|Co-emperors||Romanos IV Diogenes (1068–1071)|
Nikephoros Diogenes (1070–1071)
Michael VII Doukas (1071–1078)
Constantine Doukas (1074–1078)
Andronikos Doukas (1068–1070s)
|Reign||1078 (Senior Emperor)|
|Successor||Nikephoros III Botaneiates|
|Died||18 October 1081|
Konstantios Doukas (Greek: Κωνστάντιος Δούκας, 1060 – 18 October 1081), Latinized as Constantius Ducas, was a junior Byzantine Emperor from 1060–1078, and a senior Byzantine Emperor for a short time in 1078. Konstantios was the son of Emperor Constantine X Doukas and Empress Eudokia Makrembolitissa. Upon his birth, he was elevated to junior emperor, along with his brother Michael VII. He remained as junior emperor during the reigns of Constantine, Romanos IV Diogenes, and Michael VII, before he became senior emperor on 31 March 1078, due to the abdication of Michael VII. He was soon handed over to Nikephoros III, a usurper, due to his inability to rule. He was sent to live in a monastery, where he stayed until recalled by Alexios I Komnenos, who made him a general. He was killed on 18 October 1081, in the Battle of Dyrrhachium.
Konstantios Doukas was born in 1060, the son of Emperor Constantine X and Empress Eudokia Makrembolitissa. He was born during Constantine's reign; because of this, he was porphyrogennetos. His father Constantine became emperor on November 24, 1059, after Isaac I Komnenos selected him as his heir, shortly before Isaac abdicated.
In 1060, Constantine elevated both Michael VII and Konstantios to junior emperors under him, but did not elevate his middle son Andronikos Doukas to junior emperor, for unknown reasons. Konstantios retained his title of junior emperor during the reigns of Constantine (1060–1067), Romanos IV Diogenes (1068–1071), and Michael VII (1071–1078). Konstantios was engaged to Anna Vsevolodovna of Kiev in 1074.
Michael VII abdicated on 31 March 1078, due to severe unpopularity and the two active revolts against him by Nikephoros III and Nikephoros Bryennios, retiring to the Monastery of Stoudios. Michael VII chose Konstantios to succeed him, as Andronikos had died a few years before this.
Konstantios only had to contend with Nikephoros III, as Nikephoros Bryennios had been defeated by Nikephoros III at the Battle of Kalavrye, and subsequently blinded by him. Konstantios rapidly lost support, as it became clear he had no skill as a ruler. In the same year, his own supporters handed him over to Nikephoros III, who sent him to be tonsured and live in a monastery on one of the Princes Islands in the Propontis, as a monk. By becoming a monk he became unable to marry, and thus his engagement to Anna Vsevolodovna of Kiev was cancelled.
He was recalled by Alexios I Komnenos, who succeeded Nikephoros, and who was related to Konstantios by way of his marriage to Irene Doukaina, in 1081. He was made a general, and sent to campaign against the Normans. After Alexios seized the throne, he elevated Constantine Doukas to co-emperor. Konstantios fought in the Battle of Dyrrhachium on 18 October 1081, where Byzantine forces besieging Dyrrachium were engaged by Norman forces. Although the Byzantines were initially successful, with the Norman right wing being routed by the Byzantine left wing, the Norman center routed the central forces of the Byzantines. During this engagement, the Varangian Guard, which whom Konstantinos was fighting, was separated from the core body of the Byzantine army and massacred. Konstantinos himself perished in the combat.
Konstantios Doukas is thought to be engraved on the Holy Crown of Hungary, which was given to Hungarian King Géza I of Hungary by Konstantios' brother Michael VII, depicted alongside King Geza I and Michael VII; although the figure may actually be Constantine Doukas.
- Buckley, Penelope (2014). The Alexiad of Anna Komnene: Artistic Strategy In The Making Of A Myth. Cambridge University Press. ISBN 9781107037229.
- Finlay, George (1844), History of the Byzantine and Greek Empires from 1057–1453, 2, William Blackwood & Sons, OCLC 25020128
- Kaldellis, Anthony (2017). Streams of Gold, Rivers of Blood: The Rise and Fall of Byzantium, 955 A.D. to the First Crusade. Oxford University Press. ISBN 9780190253233.
- Norwich, John Julius (1993), Byzantium: The Apogee, Penguin, ISBN 0-14-011448-3
- Pevny, Olenka Z. (2000). Perceptions of Byzantium and Its Neighbors: 843-1261 : the Metropolitan Museum of Art Symposia. Metropolitan Museum of Art. ISBN 9780870999710.
- Savvides, Alexios G.C. (2007). Byzantino-Normannica: The Norman Capture of Italy (to A. D. 1081) and the First Two Invasions in Byzantium (A.D. 1081-1085 and 1107-1108). Peeters Publishers. ISBN 9789042919112.
- Vernadsky, George (1976) . Kievan Russia. Yale University Press. ISBN 978-0300016475.