Each group has an agenda for arguing dressage came from miliitary or the carousels.
The fact that it came from the military makes it seem noble, useful and practical. The fact that it came from the artistic carousels makes it seem like it wasn’t connected with violence and war. It makes it seem as if dressage was just perfected by masters who had as their sole desire to create an art form, away from the pressures of society, without any deadline or purpose other than just to be an art form, just to create beauty. Each position is vehemently argued.
It’s most likely that dressage didn’t come from either one exclusively, and it probably in its modern form bears very little resemblance either to the carousels OR military riding.
I have talked with quite a few scholars and historians over the years on this subject, and most military historians find it hysterical that anyone did anything remotely ‘artistic’ in battle. Especially charging on heavy armored horses in the heavy cavalry period. The idea is absurd.
War, in general, wasn’t a time for anything but the crudest horsemanship. Several famous groups even charged into battle with the bits slipped from the horse’s mouths, so that a rider couldn’t turn tail at the last minute. Riding in battle is rough, dangerous and hard.
It’s a romantic fantasy we love to perpetuate in modern times, that riding in battle involves some sort of finesse or ability to exert fine control over a charging beast in a noise filled atmosphere full of gunfire. In fact, people charged along at a dead gallop and shot at eachother, and it was very hard on man and beast alike. Read some civil war journals to discuss the injuries horses received, from their own saddles, bits and spurs, in many cases, as the riders ripped around in the saddle trying to fight.
The whole idea is that war and battle is somehow glamorous and involves some sort of refined skill is something we are in love with. It was certainly skillful how riders shot at each other, or whacked eachother with swords, without cutting their reins or their own arms off, but that’s about the end of the refined skill.
In general, I would say that most of the dressage work we do has actually very little history behind it for its exact present form. I’m sure much has been borrowed from the past in bits and pieces, but the combination of extended gaits, collected gaits, piaffe, passage, pirouette, done in the form they are done today, with no coercive equipment (check out the equipment described in pluvinel’s enlightened age in his book, if you don’t believe it), with light agile blood horses, and with a rounded back and contact with the bit, is unique in history.