Constantinople remained a Roman imperial capital for about 1,123 years , from its founding in 330 to its fall in 1453. It also stayed the capital of the Eastern Roman Empire after the Western Empire ended in 476 , which is why it’s often described as the Roman power center that outlasted Rome itself.

Quick view

  • Founded as Constantinople: 330
  • Eastern Roman capital after 476: yes
  • Fell to the Ottomans: 1453

Simple takeaway

If you mean “how long did it stay a Roman city and capital,” the answer is more than a millennium. If you mean “how long after the Western Roman Empire fell did it continue as Roman,” it lasted another 977 years from 476 to 1453.

TL;DR: Constantinople was a Roman power center for 1,123 years total and for 977 years after the West fell.