An often used, abused, and misunderstood term, classical dressage refers to ancient principles of horse training, which are based on a large knowledge pool accumulated throughout centuries by various classical riding masters. Simon of Athens and Xenophon may be termed the first known riding masters in history who issued written guidelines about how to correctly train horses for cavalry use and warfare (some ancient texts have also been found in the Kikkuli region).
Classical dressage (sometimes also referred to as classical or 'academic' equitation) is still being applied and practised by very few individuals and riding schools in this world. However, its popularity is steadily growing and classical dressage training principles may undergo a revival, especially as classical training is deemed more horse-friendly than certain modern training methods applied by some riders, for instance hyperflexion or Low-Deep-Round (here are some articles about the impact of this training method on horse health).
The term dressage is a relatively modern term and originated from the French term “dresser”, which simply means to train or tame. Academic dressage or equitation, in its original meaning, may be best described as dressage training of horse and rider at the Royal Courts (or riding academies, hence the term academic) throughout Europe during the Renaissance (foremost in Italy) and Baroque (France, England, Germany and other 'European states') period. Academic riding schools also taught the airs above the ground such as Levade, Pesade, Capriole, which are still being trained today in the four classical riding schools in Austria, Spain, Portugal and France, and also by individual classical riding masters worldwide.
Since horses were (and still are) very expensive, not only to purchase, but also to keep, maintaining good health was of utmost importance for classical dressage masters. As horses, by nature, are not straight, i.e. asymmetric (the same applies to us humans as well), classical dressage training aims to reduce a horse’s natural asymmetry through systematic application of gymnasticising exercises (beginning with the lateral movement shoulder-in on three, later on four tracks "a-la-Gueriniere", renvers, travers, walk-pirouette and reverse walk-pirouette).
Once the horse has become more supple and 'obedient', i.e. it is comfortable with being worked in-hand and knows the meaning of a whip without showing fear, the horse can be started in school walk and Piaffe ('Piaffer') in-hand. Why do we start with the Piaffe so early? Another objective of classical dressage training is to shift load from the forehand to the haunches, making horse look more uphill and lighter through collection, allowing them to perform the airs above the ground, which can only happen through many years of training and conditioning.
This said not being enough, classically trained horses further need to understand and promptly respond to the lightest rider signals administered through the rider’s aids, which are, to a large extent, based on negative reinforcement (beware: negative reinforcement differs from punishment; learn more about learning theory). Rein aids are very light and the least important aids in classical dressage, where correctly trained horses will listen to the slightest signals given by the rider's weight, seat, and legs.
The role of horses has changed in contemporary times and they are now predominantly used as leisure companions and for competitive purposes. Since the monetary value of horses is often linked to their training status and competitive success, certain modern training technologies, riding methods, and gadgets have been invented, which initially seem to speed up training processes, enabling horses to compete at higher competitive levels at an earlier age. Unfortunately, this may impact on equine health and may lead to horse wastage (i.e. slaughtering horses at an early age due to behavioural or physical problems). Hence, certain contemporary horse training methods could be termed abusive, for instance hyperflexion, which is still being practised by a large number of equestrians worldwide despite its negative impact on horse welfare. Riders as well as trainers could benefit from revisiting classical training principles and incorporating findings of equitation science in horse training guidelines to improve equine welfare over the long-term.