The Eastern Roman Empire connected Europe and Asia and had more trade access.
Explanation:
When the Roman Empire got divided into Western and Eastern Empire the power gradually started to switch toward the eastern one. The reason for this was that the Eastern Roman Empire had better strategic location, especially when it came to trade. The Eastern Roman Empire was connecting Europe and Asia, as well as having open trade with the lands north of the Black Sea through its waters.
As much of the trade was going through this part of the empire the amount of wealth was constantly increasing and pilling up. Even the Western Roman Empire became heavily dependent on the eastern one and most of the goods it obtained had to go through it, which just helped in the rise and increase of wealth even more of the Eastern Roman Empire.
