De Agricultura

Therefore, according to the most holy Moses, no man that was a breeder of horses was ever born fit for dominion; and yet some one perhaps may say that power in cavalry is a great strength to the king, not inferior either to infantry or to a naval force, but in many places far more advantageous than either, and especially in those cases in which one has need of swiftness of motion without delay, but prompt and energetic, when the times do not admit of delay, but are at the very crisis of action, so that those who arrive too late are very naturally not considered to have been sluggish so much as to have been wholly useless, the opportunity for action having passed by like a cloud.