Nicene and Post-Nicene Fathers, Ser. II, Vol I:
The Life of Constantine with Orations of Constantine and Eusebius.: Chapter VIII

p. 522 Chapter VIII.—That the Assembly was composed, as in the Acts of the Apostles, of Individuals from Various Nations.

For it is said 3243 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, 3244 while that of the presbyters and deacons in their train, and the crowd of acolytes and other attendants was altogether beyond computation.

Footnotes

Acts ii. 5sqq.

The number present is given variously as three hundred (Socrates), three hundred and eighteen (Athanasius, &c.), two hundred and seventy (Theodoret), or even two thousand (cf. Hefele). It has been conjectured that the variation came from the omission of names of the Arians (cf. note of Heinichen, Vol. 3, p. 506–507), or that it varied during the two months and more.