What contributed to the rise of the roman empire?

Rome was able to gain its empire in large part by extending some form of citizenship to many of the people it conquered.

Explanation:

Military expansion drove economic development, bringing enslaved people and loot back to Rome, which in turn transformed the city of Rome and Roman culture.  Which caused the rise of the Roman Empire.

i'd assume india mainly because of how isolated japan was.   plus it is a whole china away.

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