Dressage is an equestrian sport where a rider and their horse perform a routine of a number different movements and planned acts. The sport is measured in "tests," observed by judges, and scores that riders can receive range from 1-10, 10 being the best score. There is no contact and a test of dressage involves only a singular horse and rider. There is a small, 20x40 m arena that is used for lower levels of dressage and a larger 20x60 m arena for high level, usually professional dressage. It is slightly similar to gymnastics in that a routine for observation is shown and according to a certain criteria, is judged for score.
The concept that dressage assumes, cooperation between horse and rider, dates back to Greece about two thousand years ago. Cavalrymen realized that if the cavalry was to be victorious, horses and riders needed to be on the same page. Born from this was the training of horses to perform memorized, routine movements. In ancient Greece, this training consisted of more athletic movements, for the purpose of battle, whereas today, it consists of more textbook, basic movements in hopes of mastery and precision. After the fall of ancient Greece, the practice/sport of dressage was somewhat dormant, until the Renaissance period when a school dedicated to it opened up in Vienna, AUT.
It is hard to determine a single person that invented dressage, but it has always been known to be rooted in the writings of Xenophon. Xenophon of Athens was a student of Socrates in ancient Greece who, when Cyrus the Younger, a leader of a cavalry collective, died, got appointed to lead the stranded men. During his time leading the men, he got a lot of experience riding on horses, so he wrote about it in On Horsemanship and The Cavalry General. The affection Xenophon showed for horses have largely influenced the values and philosophy of dressage today.
Dressage can be tracked all the way back to about 400 B.C. in ancient Greece. Horsemanship was the practice of training a horse and during this time, the focus was combat-oriented as the "father of dressage," Xenophon, was a cavalry leader. The idea was maintained, but not too popular until the Renaissance period, when European elites held pageants to show off their highly skilled horses. A school then opened in Vienna, AUT in 1572 cementing the values of dressage into today's practicing. Dressage became an Olympic sport in 1912 for men, including women in the 1952 Helsinki Games. Then in the 1996 Atlanta Olympic Games, the freestyle-to-music test was added to the Dressage events.
The practice of horsemanship can be traced back to Xenophon of Athens. It started to gain some traction during the Renaissance era, when European higher-ups held pageants to showcase their highly skilled horses, but it really became popular when the Spanish Riding School in Vienna was created in 1572. Fast forward to today, it has been in the Olympics for more than a century and continues to be practiced primarily in Europe.