Similarities of Constantinople and Rome?

Both Rome and Constantinople had written laws. Emperor Justinian of Constantinople wrote the Corpus Julius Civilius which was based off the Roman written codes. Also Rome and Constantinople both practiced Christianity. Although Rome followed the Roman Catholicism and Constantinople followed the Eastern Orthodox Church, these are still from the same roots of the belief of Christianity. Also the idea of domes were used by both Rome and Constantinople. Rome had built the "Pantheon" and Constantinople built the Hagia Sophia. Emperor Justinian of Constantinople built the domes even bigger by using the quadrangle underneath the domes. Also both Rome and Constantinople were involved in trade and cultural diffusion with other countries.