Which city served as the imperial capital of both the Byzantine empire and later the Ottoman empire?

The city that served as the imperial capital of both the Byzantine Empire and later the Ottoman Empire is Constantinople. Initially founded as Byzantium, it was renamed Constantinople after Emperor Constantine the Great established it as a new capital for the Roman Empire in 330 AD. This city became the center of the Byzantine Empire for over a thousand years, known for its significant cultural, religious, and political influence during the Middle Ages.

In 1453, the city was conquered by the Ottoman Empire, which made Constantinople its capital and transformed it into a thriving metropolis that bridged Europe and Asia. The Ottomans subsequently renamed the city Istanbul, but its historical significance and legacy from both empires remain interconnected.

Other cities listed, like Rome and Alexandria, did not serve as capitals for both empires. Rome was the center of the Roman Empire but became less significant for the Byzantine Empire. Aachen was primarily a Carolingian city associated with Charlemagne and did not have ties to the Byzantine or Ottoman empires in the same way. Alexandria was an important city in ancient times but was not a capital for either of the mentioned empires.