The Alexandrinian scientist Eratosthenes of Cyrene published his topographical studies in the third century BCE. They are now lost, but the geographer Strabo of Amasia quotes their conclusion in his Geography: Alexander was responsible for a new opinion about civilization and barbarism.
The translation of Strabo, Geography, 1.4.9 was made by H.L. Jones.
Eratosthenes on Alexander
[220.127.116.11] Now, towards the end of his treatise - after withholding praise from those who divide the whole multitude of mankind into two groups, namely, Greeks and Barbarians, and also from those who advised Alexander to treat the Greeks as friends but the Barbarians as enemies - Eratosthenes goes on to say that it would be better to make such divisions according to good qualities and bad qualities.
[18.104.22.168] For not only are many of the Greeks bad, but many of the Barbarians are refined - Indians and Arians, for example, and, further, Romans and Carthaginians, who carry on their governments so admirably. And this, he says, is the reason why Alexander, disregarding his advisers, welcomed as many as he could of the men of fair repute and did them favors - just as if those who have made such a division, placing some people in the category of censure, others in that of praise, did so for any other reason than that in some people there prevail the law-abiding and the political instinct, and the qualities associated with education and powers of speech, whereas in other people the opposite characteristics prevail!
[22.214.171.124] And so Alexander, not disregarding his advisers, but rather accepting their opinion, did what was consistent with, not contrary to, their advice; for he had regard to the real intent of those who gave him counsel.