We may conveniently call it the ecumenical idea--the principle of the ecumene or inhabited world, as opposed to the principle of the polis or city.

Promoted by the vast extension of the geographical limits of the Greek world resulting from Alexander's conquests, and by his policy of breaking down the barriers between Greek and barbarian, the idea was reflected in the Stoic doctrine that all men are brothers, and that a man's true country is not his own particular city, but the ecumene.

[Footnote: Plutarch long ago saw the connection between the policy of Alexander and the cosmopolitan teaching of Zeno.

De Alexandri Magni virtute, i.Sec.

6.] It soon became familiar, popularised by the most popular of the later philosophies of Greece; and just as it had been implied in the imperial aspiration and polity of Alexander, so it was implied, still more clearly, in the imperial theory of Rome.