This appetite or impulse never does aught else but to pursue and to flee, and whenever it pursues that which is to be pursued, and as far as is right, and flies from that which is to be fled from, and as much as is right, then is the man within the limits of his perfection.

Truly, this appetite or natural impulse must have Reason for its rider; for as a horse at liberty, however noble it may be by nature, by itself without the good rider does not conduct itself well, even thus this appetite, however noble it may be, must obey Reason, which guides it with the bridle and spur, as the good knight uses the bridle when he hunts.

And that bridle is termed Temperance, which marks the limit up to which it is lawful to pursue; he uses the spur in flight to turn the horse away from the place from which he would flee away; and this spur is called Courage, or rather Magnanimity, a Virtue that points out the place at which it is right to stop, and to resist evil even to mortal combat.

And thus Virgil, our greatest Poet, represents AEneas as under the influence of powerful self control in that part of the AEneid wherein this age is typified, which part comprehends the fourth and the fifth and the sixth books of the AEneid.

And what self-restraint was that when, having received from Dido so much pleasure, as will be spoken of in the seventh treatise, and enjoying so much delectation with her, he departed, in order to follow the upright and praiseworthy path fruitful of good works, even as it is written in the fourth book of the AEneid! What impetus was that when AEneas had the fortitude alone with Sybilla to enter into Hades, to search for the Soul of his father Anchises, in the face of so many dangers, as it is shown in the sixth book of the AEneid.