Having been pardoned by Eudokia Makrembolitissa, the regent of the Byzantine Empire, for attempting to usurp the throne, Romanos IV Diogenes married her to become Byzantine emperor.

Eudokia Makrembolitissa was a Byzantine empress by her successive marriages to Constantine X Doukas and Romanos IV Diogenes. She acted as ruler with her two sons in 1067, and resigned her rule by marriage to Romanos IV Diogenes. When he was deposed in 1071 she resumed the rule with her son Michael VII, but was soon forced to resign again.

The Byzantine Empire, also known as the Eastern Roman Empire, was the continuation of the Roman Empire centred on Constantinople during late antiquity and the Middle Ages. Having survived the events that caused the fall of the Western Roman Empire in the 5th century AD, it endured until the fall of Constantinople to the Ottoman Empire in 1453. The term 'Byzantine Empire' was coined only after its demise; its citizens used the term 'Roman Empire' and called themselves 'Romans'.

Romanos IV Diogenes was Byzantine emperor from 1068 to 1071. Determined to halt the decline of the Byzantine military and to stop Turkish incursions into the empire, he is nevertheless best known for his defeat and capture in 1071 at the Battle of Manzikert, which played a major role in undermining Byzantine authority in Anatolia and allowed for its gradual Turkification.

The foundation of Constantinople in 330 AD marks the conventional start of the Eastern Roman Empire, which fell to the Ottoman Empire in 1453 AD. Only the emperors who were recognized as legitimate rulers and exercised sovereign authority are included, to the exclusion of junior co-emperors who never attained the status of sole or senior ruler, as well as of the various usurpers or rebels who claimed the imperial title.