Piazza di Siena is part of the history of Villa Borghese and it is one of the architectural and environmental jewels of the park.

The name of this square, stadium shaped and 200 meters (about 220 yards) long, comes from the Tuscan origins of the Borghese family, who owned the immense park for centuries, 93 hectares (230 acres) and 6 kilometres (3,75 miles) in perimeter.

Around the end of 1700 the Prince Marcantonio Borghese entrusted the architects Asprucci with the task of the construction of the Villa, arena included. Later on, the Piazza became famous for sacred and pagan events that took place there, attracting numerous Romans and tourists

On one side of the Square you will find the House of the Clock (Casina dell’Orologio), nowadays the municipal offices, but used in the past for different purposes. In 1832 it even became a rural restaurant, and the celebrated roman poet Giuseppe Gioacchino Belli dedicated to this event and to the patronage of the Borghese family a sonnet that became famous over the years: “Here we toast to village traditions, there there’s the ball, the orchestra, the abundance … long live the heart of Prince Borghese”
On the opposite side you will find the little Church of the Virgin (Chiesetta dell’Immacolata), built in 1792 by Mario Asprucci in a part of the building named “mulberries’ garden” where the supervisor of the Villa lived.

Piazza di Siena was opened to the public for the first time on July 2nd 1903 thanks to the donation made by the owners of the Villa to the Italian Government.
The first equestrian international competition in the arena took place in 1922 although the official editions are counted starting from 1928.