When the emperor moved to constantinople how did that affect the importance of rome?

Answer 1

Constantine's decision to designate Constantinople as the imperial capital did not have a great effect of Rome's position in the empire. Her position had been declining for some time. This was because the Romans had found it difficult to defend their frontiers along the rivers Rhine and Danube from numerous attempted invasions by outsiders. Since Rome was distant from these frontiers, she became marginalised. The frontiers areas became the important part of the empire and as a result of continuous military efforts to defend them, many emperors were humble men who had rose through the military ranks and were from Pannonia, an area along the mid-Danube. The importance of some cities along the Danube increased . Milan (in northern Italy) became very important because, being close to the Alps, it became the military base for sending troops to the frontiers along the Alps and the river Rhine and for the defence of northern Italy.

Rome had already ceased to be the imperial capital under Diocletian, Constantine's predecessor. Diocletian had designated Nicomedia (in north-western Turkey) as the imperial capital for the eastern part of the Roman Empire and Milan as the imperial capital of the western part of the empire.