It is the historic home of the Grand Priory of the Knights of Malta in Rome. The site, an important strategic place in the Middle Ages, located overlooking the Tiber, already in the tenth century it was occupied by a Benedictine fortified monastery. It then passed to the Templars and, after their removal, to the Hospitaller Knights. In 1765, the nephew of Pope Clement XIII, Cardinal Rezzonico, entrusted to Giovanni Battista Piranesi to the renovation of the result was an extraordinary place, original example of urban setting Rococo in Rome, decorated with trophies of war that allude to businesses of the Knights. The square is also known as the keyhole of the front door is framed exactly, down to the garden, the St. Peter's dome. The Villa has its ideal center in the Church of St. Mary of the Priory, inside the garden, always by Piranesi: a small building reminiscent outside the architectural model of a Roman temple, while the interior decoration complements the Baroque imagination to Classic memories.