It was referred to by its inhabitants and neighboring nations simply as the Roman Empire (in Greek Βασιλεία Ῥωμαίων, Basileia Rōmaiōn), Empire of the Romans or Romania (Ῥωμανία, Rōmaniā). Its emperorsRoman Emperors, preserving Greco-Roman legal and cultural traditions. continued the unbroken succession of
To the Islamic world it was known primarily as روم (Rûm "Rome"). Due to the linguistic, cultural, and demographic dominance of medieval Greek it was known to many of its western European contemporaries as Imperium Graecorum, the Empire of the Greeks (see also the etymology section).
The definition of this empire as a distinct entity in itself constitutes an implicit or explicit rejection of its emperors and people's claim to be Romans and succesors of the Roman Empire - a rejection based on the assumption that only an empire using Latin as its official language and based in Italy can be considered truly "Roman", and that geographical move into hellenistic territory and linguistic-cultural adoption of Greek constituted a transformation into an inherently different identity.
The Eastern Roman Empire's evolution into a different culture from the ancient Roman Empire can be seen as a process beginning when the Emperor Constantine transferred the capital from Nicomedia in Anatolia to Byzantium, which was renamed New Rome or Constantinople, on the Bosphorus.
By the 7th century, under the reign of Emperor Heraclius, whose reforms changed the nature of the Empire's military and recognized Greek as the official language, the Empire had taken on a distinct new character.
During its thousand-year existence the Empire suffered numerous setbacks and losses of territory but remained one of the most powerful economic, cultural and military forces in Europe. The empire's influence also spread into North Africa and the near East for much of the Middle Ages.
After a final recovery under the Komnenian dynasty in the 12th century the Empire slipped into a long decline culminating in the capture of Constantinople and the remaining territories by the Ottoman Turks in the 15th century.
The Empire, a bastion of Christianity and one of the prime trade centers in the world, helped to shield Western Europe from early Muslim expansion, provided a stable gold currency for the Mediterranean region, influenced the laws, political systems, and customs of much of Europe and the Middle East, and preserved much of the literary works and scientific knowledge of ancient Greece, Rome, and many other cultures.