Final answer:
Access to the Silk Road contributed to the eastern capital's wealth by providing a trade route for luxury goods from China and India.
Step-by-step explanation:
The geographical feature that contributed to the eastern capital's wealth was access to the Silk Road.
As the capital of the Byzantine Empire, Constantinople was a major terminus point of the Silk Road, which brought a rich array of raw substances and finished goods from China, India, and beyond. This trade route allowed for the import of luxury goods such as spices, dyes, and silks, which were then resold throughout Europe.
The trade along the Silk Road generated substantial surpluses, leading to significant investment in mining and agriculture, which further contributed to the wealth of the eastern capital.