When were riding arenas first used?

Riding arenas, or enclosed spaces designed for equestrian activities, have been in use since ancient times, with evidence of their existence dating back to at least the Roman Empire. However, the modern concept of a riding arena began to take shape in the 19th century, particularly in Europe, as equestrian sports gained popularity. These arenas provided a controlled environment for training and competitions, leading to their widespread adoption in the equestrian community.