During the collapse of the Roman Empire in the West, the Byzantine Empire rose to power in the east centered around the capital city of Constantinople now located in which country?

The Byzantine Empire, which emerged following the decline of the Western Roman Empire, had its capital at Constantinople. Today, the site of Constantinople is located in modern-day Turkey. This city, originally known as Byzantium, was re-established as Constantinople by Emperor Constantine the Great in 330 A.D. It served as the center of the Eastern Roman Empire and later the Byzantine Empire for over a thousand years until its conquest by the Ottoman Turks in 1453. The strategic geographical position of Constantinople allowed it to control key trade routes between Europe and Asia, which significantly contributed to its prominence and power throughout Byzantine history.

The other choices reference regions that either no longer exist as entities that match their historical significance or are not related to the capital of the Byzantine Empire, making Turkey the accurate answer in the context of this question.