That the Assembly was composed, as in the Acts of the Apostles, of Individuals from Various Nations
For it is said that in the Apostles' age, there were gathered “devout men from every nation under heaven”; among whom were Parthians, and Medes, and Elamites, and the dwellers in Mesopotamia, in Judea, and Cappadocia, in Pontus and Asia, in Phrygia and Pamphylia, in Egypt, and the parts of Libya about Cyrene; and sojourners from Rome, both Jews and proselytes, Cretans and Arabians. But that assembly was less, in that not all who composed it were ministers of God; but in the present company, the number of bishops exceeded two hundred and fifty, while that of the presbyters and deacons in their train, and the crowd of acolytes and other attendants was altogether beyond computation.
Source: Life of Constantine (New Advent)