Romanos IV Diogenes was Byzantine emperor from 1068 to 1071, ruling during one of the most critical periods in the empire’s medieval history. A member of the military aristocracy of Cappadocia, he rose to power through marriage to the empress Eudokia Makrembolitissa, widow of Emperor Constantine X Doukas. With the support of the army, he was proclaimed emperor in 1068, assuming responsibility for defending the empire’s increasingly threatened eastern frontier.

Romanos sought to restore Byzantine authority in Asia Minor, which had been subjected to repeated incursions by the Seljuk Turks. Between 1068 and 1071 he led several campaigns in Armenia and eastern Anatolia in an effort to stabilize the frontier and rebuild imperial military strength. His efforts culminated in the campaign that led to the Battle of Manzikert in 1071, where his army was defeated by the Seljuk forces of Sultan Alp Arslan, and the emperor himself was captured.

Although Alp Arslan treated his prisoner with relative leniency and released him after negotiating terms, the political situation in Constantinople had changed during his captivity. The Doukas faction seized power and proclaimed Michael VII Doukas emperor. When Romanos attempted to reclaim the throne, he was defeated by forces loyal to the new regime. In 1072 he was captured, blinded, a common Byzantine method of permanently removing political rivals, and exiled to the island of Proti in the Sea of Marmara, where he died soon afterwards, likely from infection caused by the blinding.

The defeat at Manzikert and the subsequent civil conflict weakened Byzantine authority in Anatolia, opening much of the region to Turkish settlement and marking a major turning point in the history of the Byzantine Empire.