The correct chronological order is as follows:
Fall of the Western Roman Empire.
The <em>Western Roman Empire</em> fell in in 476 AD.
Gregory I becomes pope.
<em>Gregory I becomes pope</em> in 590 AD.
Height of the medieval period.
The <em>medieval period peaked</em> around 1000 - 1300 AD, or <em>1150 AD</em> if you take the mean.
Fall of the Eastern Roman Empire.
The Eastern Roman Empire, or the <em>Byzantine Empire</em>, <em>fell at 1453</em>.
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Learn more about the Roman Empire (West & East):
brainly.com/question/11415671?referrer=searchResults - The different churches followed by the respective halves of the empire.
brainly.com/question/20369245?referrer=searchResults - The result of moving the capitol to Byzantine, away from Rome.