Xenophon...

"For what the horse does under compulsion, as Simon also observes, is done without understanding; and there is no beauty in it either, any more than if one should whip and spur a dancer."

"The hand must neither hold so strict as to confine and make the horse uneasy, nor so loosely as not to let him feel it. The moment he obeys and answers it, yield the bridle to him; this will take off the stress and relieve his bars, and is in conformity with that maxim, which should never be forgot, which is to caress and reward him for whatever he does well. The moment that the rider perceives that the horse begins to place his head, to go lightly in the hand, and with ease and pleasure to himself; he should do nothing that is disagreeable, but flatter and coax, suffer him to rest a while, and do all he can to keep him in this happy temper. This will encourage and prepare him for greater undertakings."
Xenophon 444-365 BC.