The Byzantine Empire, also referred to as the Eastern Roman Empire, or Byzantium, was the continuation of the Roman Empire in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantinople. It survived the fragmentation and fall of the Western Roman Empire in the 5th century AD and continued to exist for an additional thousand years until it fell to the Ottoman Empire in 1453. During most of its existence, the empire was the most powerful economic, cultural, and military force in Europe.
"Byzantine Empire" is a term created after the end of the realm; its citizens continued to refer to their empire simply as the Roman Empire or Romania, and to themselves as Romans - a term which Greeks continued to use for themselves into Ottoman times. Although the Roman state continued and its traditions were maintained, modern historians distinguish Byzantium from its earlier incarnation because it was centred on Constantinople, oriented towards Greek rather than Latin culture, and characterised by Eastern Orthodox Christianity.