Training embraces two slightly different concepts, one arising from the other. Firstly, horses and riders must be taught all the basic skills, and following this the secondary implication of training is that of practice and exercise to maintain the skills once learned. A horse must first be trained to accept a rider on his back and to obey commands which are conveyed to him in a variety of ways. A new recruit must be trained to ride not just one horse but to perform all the required manoeuvres on any horse. In other words he must be trained in horsemanship. Thereafter, beyond the initial training, horses and soldiers must keep their skills up to standard by continual drill and exercises in the field, as Vegetius pointed out (Epitoma Rei Militaris 2.23): ‘The very essence of an art consists in constant practice.’ Quite apart from the training and subsequent practice, horses must be regularly exercised if they are to be kept in fit condition and ready for action (see p.218ff).