And God proclaims as a first principle to the rulers, and above all else, that there is nothing which they should so anxiously guard, or of which they are to be such good guardians, as of the purity of the race.
They should observe what elements mingle in their offspring; for if the son of a golden or silver parent has an admixture of brass and iron, then nature orders a transposition of ranks, and the eye of the ruler must not be pitiful towards the child because he has to descend in the scale and become a husbandman or artisan, just as there may be sons of artisans who having an admixture of gold or silver in them are raised to honour, and become guardians or auxiliaries.

For an oracle says that when a man of brass or iron guards the State, it will be destroyed.

Such is the tale; is there any possibility of making our citizens believe in it?
Not in the present generation, he replied; there is no way of accomplishing this; but their sons may be made to believe in the tale, and their sons' sons, and posterity after them.
I see the difficulty, I replied; yet the fostering of such a belief will make them care more for the city and for one another.

Enough, however, of the fiction, which may now fly abroad upon the wings of rumour, while we arm our earth-born heroes, and lead them forth under the command of their rulers.

Let them look round and select a spot whence they can best suppress insurrection, if any prove refractory within, and also defend themselves against enemies, who like wolves may come down on the fold from without; there let them encamp, and when they have encamped, let them sacrifice to the proper Gods and prepare their dwellings.
Just so, he said.
And their dwellings must be such as will shield them against the cold of winter and the heat of summer.
I suppose that you mean houses, he replied.
Yes, I said; but they must be the houses of soldiers, and not of shop-keepers.
What is the difference?
he said.
That I will endeavour to explain, I replied.