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The Byzantine Empire, with its capital in Constantinople, was ruled by Emperor Romanos IV Diogenes from 1068 to 1071. His reign was marked by military conflicts, particularly the Battle of Manzikert against the Seljuk Turks, which resulted in his capture and subsequent release. Despite attempts to strengthen the empire's defenses, Romanos faced internal challenges and was eventually overthrown by a rebellion led by Michael VII Doukas.