[lioeters]

Not being familiar with the history, the dates that I found seem to support your point.

> The Plague of Justinian (541–549 AD)

> The Byzantine Empire, also referred to as the Eastern Roman Empire..[was] in 555 under Justinian the Great, at its greatest extent since the fall of the Western Roman Empire.

> It survived the fragmentation and fall of the Western Roman Empire in the 5th century AD and continued to exist for an additional thousand years until it fell to the Ottoman Empire in 1453.