William Cavendish quotes:

You must in all Airs follow the strength, spirit, and disposition of the horse, and do nothing against nature; for art is but to set nature in order, and nothing else.

Be always lavish of your caresses, and sparing in your corrections.

These are excellent lessons to break him, and make him light in hand: but nothing puts a horse so much upon his haunches, and consequently makes him so light in hand, as my new method of the pillar.

But my method of the pillar, as it throws the horse yet more upon the haunches, is still more effectual to this purpose, and besides always gives him the ply to the side he goes of.

You should pull him back besides in all the lines before the quarter, just as you make the others advance.

The horse's neck is between the two reins of the bridle, which both meet in the rider's hand.

The main secret for a horse that is heavy upon the hand, is for the rider to have a very light one; for when he finds nothing to bear upon with his mouth, he infallibly throws himself upon the haunches for his own security.

Use gentle means before you come to extremity, and whatever lesson you work him, and never take above half his strength, nor ride him till he is weary, but a little at a time and often.

But we ought to consider the natural form and shape of a horse, that we may work him according to nature.

By this way you may dress all sorts of horses in the utmost perfection, if you know how to practice it; a thing that is very easy in the hands of a master.

And he that said that a horse was not dressed, whose curb was not loose, said right; and it is equally true that the curb can never play, when in its right place, except the horse be upon his haunches.

Now being upon the haunches (as he necessarily must be in this case) is it impossible but he must be light in hand, because no horse can be rightly upon his haunches without being so.