Both were imperialistic.
Both were threatened by nomadic invaders.
Both economies were based on agriculture.
Both were weakened from over expansion.
Answer:
trade and industry grew
more people moved to rural area to farm.
The Roman Empire had grown so vast due to conquering vast amounts of land that it was no longer feasible to govern all the provinces from the central seat of Rome. So, Emperor Diocletian divided the empire into halves with the Eastern Empire governed out of Byzantium, and the western portion of the empire governed out of Rome.
