[111] The mind, therefore, having called in these allies, says, "Let us build ourselves a city;" an expression equivalent to, Let us fortify our own things; let us fence them around to the best of our power, so that we may not be easily taken by those who attack us; let us divide and distribute, as into tribes and boroughs, each of the powers existing in the soul, allotting some to the rational part, and some to the irrational part;