Depiction of Egyptians and Arabs in Rome. They did no mistakes. They depicted the evidence they knew, the evidence they saw.

Depiction of Egyptians and Arabs in Rome. They did no mistakes. They depicted the evidence they knew, the evidence they saw. 

Herodotus:

“I myself guessed it to be so, partly because they are dark-skinned and woolly-haired; though that indeed goes for nothing, seeing that other peoples, too, are such; but my better proof was that the Colchians and Egyptians and Ethiopians are the only nations that have from the first practiced circumcision”.  

"Herodotus, The Histories Book II Chapters 99-182"

Diodorus Siculus:

“They say also that the Egyptians are colonists sent out by the Ethiopians, Osiris having been the leader of the colony… And the larger part of the customs of the Egyptians are, they hold, Ethiopian, the colonists still preserving their ancient manners…Furthermore, the orders of the priests, they maintain, have much the same position among both peoples; for all are clean​ who are engaged in the service of the gods, keeping themselves shaven, like the Egyptian priests, and having the same dress and form of staff, which is shaped like a plough and is carried by their kings, who wear high felt hats which end in a knob at the top and are circled by the serpents which they call asps; and this symbol appears to carry the thought that it will be the lot of those who shall dare to attack the king to encounter death-carrying stings.​ Many other things are also told by them concerning their own antiquity and the colony which they sent out that became the Egyptians, but about this there is no special need of our writing anything…We must now speak about the Ethiopian writing which is called hieroglyphic among the Egyptians…”

The Library of History of Diodorus Siculus Vol II, Book III