Domitian’s Stadium (Circus Agonalis) is the earliest example of a masonry stadium of Greco-Roman antiquity, reserved for athletic competitions (running, wrestling, boxing); it is located close to Piazza Navona. Its ground level was about 5 metres lower than the current level.
It was built in the Campus Martius between 85-86 A.D. by Domitian, both to offer the people an additional venue for celebrations (and praise of the emperor) and to satisfy the imperial passion for athletics.