Konstantios Doukas

Konstantios Doukas
Co-emperor of the Byzantine Empire
Gold histamenon of Romanos IV: Michael VII flanked by his brothers Andronikos and Konstantios on the obverse, Romanos IV and Eudokia Makrembolitissa crowned by Christ on the reverse
Reign	1060–1078
Predecessor	Michael VII
Successor	Nikephoros III Botaneiates
Born	1060
Died	1082
Dynasty	Doukid dynasty
Father	Constantine X
Mother	Eudokia Makrembolitissa

Konstantios Doukas (Greek: Κωνστάντιος Δούκας, 1060–1082), Latinized as Constantius Ducas, was the son of Byzantine Emperor Constantine X Doukas and younger brother of Byzantine Emperor Michael VII Doukas. He reigned as junior co-emperor from his birth, but was unable to establish himself as sole emperor against Nikephoros III when Michael VII abdicated in 1078.

Konstantios was the youngest son of Constantine X Doukas and was born a porphyrogennetos. Upon his birth he was made co-emperor, alongside his brother Michael VII Doukas. His other brother, Andronikos Doukas, was also elevated some eight years later. He retained the imperial title during the reigns of Romanos IV Diogenes and his elder brother, Michael VII, as senior emperors. In 1078, when Michael's reign came to an end by an insurrection at Constantinople, he abdicated in favour of Konstantios, as Andronikos had apparently died a year or two before. His only rival was Nikephoros III, who was on his way to Constantinople when news arrived of Michael's overthrow.

It was soon manifestly evident that Konstantios was completely incapable of leading the empire. Although the troops in Asia Minor also proclaimed him emperor, his incapacity was soon so evident that his own supporters swiftly delivered him to Nikephoros III, who forced him to become a monk, taking up his residence on one of the Princes Islands in the Propontis.

By 1081, he was recalled into active service by Alexios I Komnenos, who had married into the Doukas family. Sent to the war against the Normans, he perished while fighting them at Dyrrhachium in 1082.