1. Byzantine empire was far more richer than Western Roman Empire. Western Empire was poorly developed and populated compared to the East, with thriving cities such as Constantinople and Alexandria.
2. Diplomacy: he Byzantines had enemies by all sides, and limited military power for that reason. However, the wealth of the Eastern Empire allowed them to create and develop a more effective diplomacy and divert barbarians to the west.
3. Falling domestic population in Western Empire, and rapidly populatng neighbours (Germanic Tribes) who find themselves hungry or pushed out of their homes by another expansionist power (Huns), together put enormous pressure on the Borders of the Roman Empire, because they were extremely undeveloped and weak compared to Romans, they had more advanced troops, and could have beaten troops, but only if they came by one, not all together, as actually happened.
