This was a Quora question. I like this question – one of my pet moans about 19th century historians. When Gibbon described the Decline & Fall of the Roman Empire in the 18th century he meant the Empire until it’s final fall in 1453.
One big problem in interpreting history is that it is always approached from the from the standpoint and using the values of the historian’s own day and society. Often these values are ones that the people only perceive to be of their own day. So people look at the brutality of the Spanish Inquisition who tortured and burnt, Jews, Muslims and heretics, or the brutality of medieval and Tudor times and believe we are “ civilised” now. Yet the 20th century encompassed more brutality and human slaughter than at any time in human history. Apart from two world wars, to be Jewish in Germany was a death sentence. To be an actual Marxist in Stalin’s Russia was a death sentence. To be South Vietmese peasant was as likely as not be a death sentence and of course many more. Today to be Muslim in Burma ? To be Muslim in Serbia, to be Muslim in Israel? To be a Christian in Syria?
Anyway back to the Roman Empire. To the average person the Roman Empire fell in 5th century and was followed by the “ dark ages”.
This was the western centric view. The Empire that carried on in the east was redesignated by 19 th century historians as the “ Byzantine” Empire – something very foreign and rather exotic. They were not proper Romans because they spoke Greek. Western rulers were very keen to emulate what they thought the ancient Greeks and Romans to be. The American constitution includes a Senate, an upper house of wisdom, Capitol Hill itself is a tribute to the Romans. Napoleon saw himself as the Caesar of a new Roman Empire. The British thought that Parliament was like classical Athens, the Spartans – a more successful state in many ways – were crude by comparison. Palmerston’s marathon speech to the House of Commons summed it up with the subject of “Pax Britannica”. Britannia herself, symbolises Britain is depicted as a Roman goddess. While western society loved the ancient Greeks, as the foundation of modern culture – actual Greeks, the ones were regarded as Eastern, untrustworthy and lacking culture not even to be trusted with ancient monuments – Elgin clearly regarded Britain as in the inheritor of Graeco Roman culture – not the modern Greeks, so long under Turkish rule.. This is why Roman Empire was Latin and not Greek. The “real” Roman Empire was Latin and ended in 427, the rest became Byzantium, a Medieval Greek Empire.
But the actual history is different. When you look at a map of the Roman Empire at its greatest extent it’s eady to see that the major cities, the main ports are in the east, Corinth, Ephesus, Antioch, Nicaea, Byblos, Caesarea, Jerusalem, Alexandria among the main ones. All through the Middle Ages the mightiest City of all, with a population at its height in the 8th & 10th centuries exceed 1,000,000 was Constantinople . Excepting towns in Provence, towns in West were trifling. Throughout the history of the Empire the balance of trade and production was in the east. Anatolia and Egypt were the bread baskets of the Empire. Everywhere in the east Greek was spoken as the lingua franca. Rome itself became too remote, too peripheral. The decision by Constantine I to move Rome to the small Greek village of Byzantium. So the new Capital was called New Rome, after his death, it was designated “ The New Rome that is called Constantinople”. After Justinian, who had built the wondrous Hagia Sophia, Latin ceased to be language of government. From that time onwards the government language was Greek. But they were Romans, for them Roman meant civilisation, it meant the known world. The last Emperor Constantine XI who died defending the city on the walls of Constantinople in 1453 was designated “ Roman Emperor “.
However, looking from a people’s point of view, the Roman Empire was fundamentally a slave economy – the foundation of which was the high productivity ( relatively) in the Eastern half. While trade – as far as China and Sri Lanka flourished, this enabled cities like Constantinople, Antioch, Adrianople etc to become very large. As it shrank because of growth of Islamic states on the one hand and Western Europe’s ( particularly Italy) slow emergence from feudalism, together with the continued movement of peoples fro east to west, it became more petrified into feudal like structure.