Xenophon On the Art of Horsemanship 10

[1]
  If a man wants to make a useful war-horse look more stately and showy when ridden, he must avoid pulling his mouth with the bit, and using the spur and whip, means by which most people imagine that they show off a horse. In point of fact the results they produce are the very opposite of what they intend.

[2] For by dragging the mouth up they blind their horses instead of letting them see ahead, and by spurring and whipping, flurry them so that they are startled and get into danger. ¹ That is the behaviour of horses that strongly object to being ridden and that behave in an ugly and unseemly fashion.

[3] But if you teach the horse to go with a slack bridle, to hold his neck up and to arch it towards the head, you will cause the horse to do the very things in which he himself delights and takes the greatest pleasure.

[4] A proof that he delights in them is that whenever he himself chooses to show off before horses, and especially before mares, he raises his neck highest and arches his head most, looking fierce; he lifts his legs freely off the ground and tosses his tail up.

[5] Whenever, therefore, you induce him to carry himself in the attitudes he naturally assumes when he is most anxious to display his beauty, you make him look as though he took pleasure in being ridden, and give him a noble, fierce, and attractive appearance. How we think that these effects may be produced we will now try to explain.

[6]
  To begin with, you should possess two bits at least. ² One of these should be smooth and have the discs of a good size; the other should have the discs heavy and low, and the teeth sharp, so that when the horse seizes it he may drop it because he objects to its roughness, and when he is bitted with the smooth one instead, may welcome its smoothness and may do on the smooth bit what he has been trained to do with the aid of the rough one.

[7] In case, however, he takes no account of it because of its smoothness, and keeps bearing against it, we put large discs on the smooth bit to stop this, so that they may force him to open his mouth and drop the bit. It is possible also to make the rough bit adaptable by wrapping ³ it up and tightening the reins. ⁴

[8] But whatever be the pattern of the bits, they must all be flexible. For wherever a horse seizes a stiff one, he holds the whole of it against his jaws, just as you lift the whole of a spit wherever you take hold of it.

[9] But the other kind of bit acts like a chain: for only the part that you hold remains unbent, while the rest of it hangs loose. As the horse continually tries to seize the part that eludes him in his mouth, he lets the bit drop from his jaws. This is why little rings ⁵ are hung in the middle on the axles, in order that the horse may feel after them with his tongue and teeth and not think of taking the bit up against the jaws.

[10]
  In case the meaning of the terms flexible and stiff as applied to a bit is not known, we will explain this too. Flexible means that the axles have broad and smooth links so that they bend easily; and if everything that goes round the axles ⁶ has large openings, and does not fit tight, it is more flexible.

[11] Stiff, on the other hand, means that the pieces of the bit do not run over the axles and work in combination easily.

  Whatever the pattern may be, the same method of using it must be carried out in all the points that follow, assuming that you want your horse to have just the appearance I have described.

[12] The mouth must neither be pulled so hard that he holds his nose in the air, nor so gently that he takes no notice. As soon as he raises his neck when you pull, give him the bit at once. Invariably, in fact, as we cannot too often repeat, you must humour you horse whenever he responds to your wishes.

[13] And when you notice that high carriage of his neck and lightness of hand give him pleasure, you should not deal hardly with him as though you were forcing him to work, but coax him as when you want to stop ⁷ ; for thus he will break into a fast pace with most confidence.

[14] There is plain proof that a horse takes pleasure in going fast: for when he breaks loose a horse never goes at a walking pace, but always runs. He instinctively takes pleasure in this, provided he is not compelled to run too far for his strength. Nothing in excess is ever pleasing either to horse or man.

[15]
  When your horse has progressed so far as to bear himself proudly when ridden, he has, of course, already been accustomed in the early exercises to break into a quicker pace after turning. ⁸ Now if after he has learnt this you pull him up with the bit and at the same time give him one of the signs to go forward, then being held back by the bit and yet roused by the signal to go forward, he throws his chest out and lifts his legs from the ground impatiently, but not with a supple motion; for when horses feel uncomfortable, the action of their legs is not at all supple.

[16] But if, when he is thus excited, you give him the bit, then, mistaking the looseness of the bit for a deliverance from restraint, he bounds forward for very joy with a proud bearing and supple legs, exultant, imitating exactly in every way the graces that he displays before horses.

[17] And those who watch the horse when he is like that call him well-bred, a willing worker, worth riding, mettlesome, magnificent, and declare his appearance to be at once pleasing and fiery.

  And here we conclude these explanations addressed to those who want this sort of thing.