Much of what the ancient authors have to say about the ideal qualities of a horse appertains to racers and chariot horses rather than to cavalry mounts, but at least it was recognized that different characteristics were necessary in horses intended for different purposes. Varro (De Re Rustica 2.7.15) lists the qualities of horses to be used for warfare, transport, breeding and the circus, and Vegetius (Ars Mulomedicinae 3.6.2) divides horses into three categories: for war, the circus and for riding, with the best types for each category. As Varro points out, all horses should not be judged and valued by the same standards.