Sidesaddle riding is a form of equestrianism that uses a type of saddle which allows a rider (usually female) to sit aside rather than astride an equine. Sitting aside dates back to antiquity and developed in European countries in the Middle Ages as a way for women in skirts to ride a horse in a modest fashion while also wearing fine clothing. It has retained a specialty niche even in the modern world.
The earliest depictions of women riding with both legs on the same side of the horse can be seen in Greek vases, sculptures, and Celtic stones. Medieval depictions show women seated aside with the horse being led by a man, or seated on a small padded seat (a pillion) behind a male rider. Ninth century depictions show a small footrest, or planchette added to the pillion. These designs did not allow a woman to control a horse; she could only be a passenger.
In Europe, the sidesaddle developed in part because of cultural norms which considered it unbecoming for a woman to straddle a horse while riding. Further, long skirts were the usual fashion and riding astride in such attire was often impractical, awkward, and could be viewed as immodest. However, women did ride horses and needed to be able to control their own animals, so there was a need for a saddle designed to allow both control of the horse and modesty for the rider.
The earliest functional "sidesaddle" was credited to Anne of Bohemia (1366–1394). It was a chair-like affair where the woman sat sideways on the horse with her feet on a small footrest. The design made it difficult for a woman to both stay on and use the reins to control the horse, so the animal was usually led by another rider, sitting astride. The insecure design of the early sidesaddle also contributed to the popularity of the Palfrey, a smaller horse with smooth ambling gaits, as a suitable mount for women.