(APEX) Two once mighty empires were collapsing because of internal strife and foreign invasions.
In the 1400's there was no Byzantine Empire, so there is no comparison. The Roman Empire was formed from the Byzantine Empire.
The Byzantine empire was where the eastern empire of Rome used to be, with its capital being Constantinople.
Alexios I Comnenos, Constantinople
During the Byzantine Empire.
The Capital of the Byzantine Empire was originally called Byzantium before being renamed as Constantinople (which was its name during its control by the Byzantine Empire) and renamed by Ottomans as Istanbul afterwards. Constantinople was the capital of the Byzantine empire
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The state religion of the Byzantine Empire, during the entire time we refer to it by that name, was Christianity.
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Islam became a rival of Christianity in the Byzantine Empire.
400 - 1400, during the era when the Roman Empire declined, the Byzantine Empire flourished, and Islam was founded.
Islam became the strongest rival of Christianity in the Byzantine Empire.
Matthew Kantakouzenos
During the Byzantine Empire, it was founded in Norway.