I have some questions about ethnicities in Roman Empire, which are linked with each other.

1. Is there any Information about the number of different cultural and ethnic groups in Roman Empire? For example, how many ethnic Romans, Carthagians, Greek, Gaul, Numidians and other lived in Roman Empire, lets say in the year 0, or 100 AD, or other dates.

2. In the New Testament of the Bible, we find this: „Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language. And they were all amazed and marvelled, saying one to another, Behold, are not all these which speak Galilaeans? And how hear we every man in our own tongue, wherein we were born? Parthians, and Medes, and Elamites, and the dwellers in Mesopotamia, and in Judaea, and Cappadocia, in Pontus, and Asia, Phrygia, and Pamphylia, in Egypt, and in the parts of Libya about Cyrene, and strangers of Rome, Jews and proselytes, Cretans and Arabians, we do hear them speak in our tongues the wonderful works of God.“ ‭‭ According to this, it seems, that people from many different places lived in ancient Jerusalem. Was it normal for big Roman cities? Did other big cities like Carthago, Syrakus or Antiochia also had such big ethnic diversity?

3. And last, was it normal for people to move to an other place, like from Crete to Jerusalem or from North Africa to Roman Germania for example. And how common was the Migration from other countries (in the Bible verses I mentioned there are also people from parthia, which wasnt Part of the roman Empire). And did people have to register anywhere when they moved to Roman Empire?

Sorry for the long text.