When did the empire of Charlemagne and the Byzantine Empire flourish under Justinian?

Charles’s empire reached its zenith in 800. True, after his death in 814, internal strife began in the country. So a few decades later, in 843, the lands of the empire were divided between three heirs during the signing of the Treaty of Verdun.

The Byzantine Empire reached its peak in the period 527-565. Then Justinian not only strengthened the country from the inside, but was also able to return a significant part of the lost territories, as well as pacify many barbarian tribes on the borders.