Historiography of the fall of the Western Roman Empire Historiography of the fall of the Western Roman Empire The causes and mechanisms of the Fall of the Western Roman Empire are a historical theme that was introduced by historian Edward Gibbon in his 1776 book "The History of the Decline and Fall of the Roman Empire". He started an ongoing historiographical discussion about what caused the Fall of the Western Roman Empire, and the reduced power of the remaining Eastern Empire, in the 4th–5th centuries. Gibbon was not the first to speculate on why the Empire collapsed, but he was the first to give a well-researched and well-referenced account.
Decline of the Byzantine Empire fell into decline. After the Battle of Manzikert (1071) it lost control of Anatolia, and while the Komnenos dynasty restored a degree of stability in the 12th century with help from the First Crusade, the empire was captured and partitioned by the Crusaders themselves in the Fourth Crusade in 1204. Even after Byzantine 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 conquered with the Fall