The Byzantine Empire (or Byzantium) was the predominantly Greek-speaking eastern part of the Roman Empire throughout Late Antiquity and the Middle Ages. Also known as the Eastern Roman Empire, the Byzantine Empire was called simply Roman Empire or Romania (Greek: Ῥωμανία, Rhōmanía) by its inhabitants and neighbours. Centered on the capital of Constantinople, it was ruled by emperors in direct succession to the ancient Roman emperors after the collapse of Western Roman Empire. As the distinction between "Roman Empire" and "Byzantine Empire" is largely a modern convention, it is not possible to assign a date of separation, but an important point is Emperor Constantine I's transfer in 324 of the capital from Nicomedia (in Anatolia) to Byzantium on the Bosphorus, which became Constantinople (alternatively "New Rome").[n 1]
The Byzantine Empire existed for more than a thousand years (from approximately 306 AD to 1453 AD). During its existence, the Empire remained one of the most powerful economic, cultural, and military forces in Europe, despite setbacks and territorial losses, especially during the Roman–Persian and Byzantine–Arab Wars. The Empire recovered during the Macedonian dynasty, rising again to become a pre-eminent power in the Eastern Mediterranean by the late 10th century, rivaling the Fatimid Caliphate. After 1071, however, much of Asia Minor, the Empire's heartland, was lost to the Seljuk Turks. The Komnenian restoration regained some ground and briefly re-established dominance in the 12th century, but following the death of Andronikos I Komnenos and the end of the Komnenos dynasty in the late 12th century the Empire declined again. The Empire received a mortal blow in 1204 by the Fourth Crusade, when it was dissolved and divided into competing Byzantine Greek and Latin realms. Despite the eventual recovery of Constantinople and re-establishment of the Empire in 1261, under the Palaiologan emperors, successive civil wars in the 14th century further sapped the Empire's strength. Most of its remaining territories were lost in the Byzantine–Ottoman Wars, which culminated in the Fall of Constantinople and the ceding of its remaining territories to the Muslim Ottoman Empire in the 15th century.