Decline of the Byzantine Empire

The Byzantine Empire (the Eastern Roman Empire during the medieval period, after the fall of the Western Roman Empire) following the crisis of the managed to re-establish itself in a golden age under the Justinian dynasty in the 6th century, and during the Early Middle Ages it continued to flourish even after the Muslim conquest of the Levant and the constant threat of Arab invasion.

But in the High Middle Ages, under pressure from the Seljuk Empire, it entered a period of continuous decline. After the Battle of Manzikert (1071) it lost control of Anatolia, and while the Crusades provided a respite from the threat of Islamic expansion during the 12th century, the empire was captured by the Crusaders themselves in the Fourth Crusade in 1204.

Even after Roman rule was restored in 1261, the empire was now a shadow of its former self, and after the end of the Crusades, the empire had little to set against the rise of the Ottoman Empire during the late medieval period, and was eventually destroyed with the Fall of Constantinople in 1453.

The process by which the empire waned, and from when its decline can be traced, is a matter of scholarly debate. In some cases, the entire history of the Byzantine Empire has been portrayed as a protracted period of decline of the Roman Empire. This holds especially for Enlightenment era writers such as Edward Gibbon, author of The History of the Decline and Fall of the Roman Empire, published in six volumes between 1776 and 1789, whose view was coloured by pro-western or anti-clerical biases, and tended to see the whole ten-century empire as merely a sad codicil to the Roman Empire of Antiquity.

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Wikipedia