Aelius Aristeides: To Rome (A.D. 143)
Far more worthy of examination and wonder than all else is your citizenship and the magnificence of its concept, for there is nothing like it anywhere.
Having divided into two groups all peoples in your empire having used this word, I mean to say the whole inhabited world you have defined the more accomplished, the more high-minded, and the more powerful civic body, or (one might say) everything that is of the same breed as yourself, while the rest of the empire is a mere subject under your rule.
The sea is not a hindrance to becoming a citizen, nor is the mass of the intervening land, nor is any distinction made here between Asia and Europe. Everything lies within reach of everyone. Nobody is a stranger who is worthy of magistracy or trust, but a free republic in which the whole world shares, has been established under one excellent ruler and director, and everyone meets as if in a common assembly, each to receive his just reward.
(From Sherk, Robert K. (ed.), The Roman Empire: Augustus to Hadrian (Cambridge 1988) 164.)