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 significant factors in the decline of the Byzantine empire. As one of the main institutional strengths of the Byzantine state, the theme system was never replaced by a viable long-term alternative. This left the empire lacking in underlying structural strengths. The result was an empire that depended more than ever before on the strengths of each individual emperor or dynasty. The collapse of imperial power and authority after 1185 revealed the inadequacy of this approach. 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