The Republic by Plato Part 4 Page 12

and you would be altogether beside the mark if you treated them all as a single State. But if you deal with them as many, and give the wealth or power or persons of the one to the others, you will always have a great many friends and not many enemies.

And your State, while the wise order which has now been prescribed continues to prevail in her, will be the greatest of States, I do not mean to say in reputation or appearance, but in deed and truth, though she number not more than a thousand defenders. A single State which is her equal you will hardly find, either among Hellenes or barbarians, though many that appear to be as great and many times greater.

That is most true, he said.

And what, I said, will be the best limit for our rulers to fix when they