The name Piazza d’Oro (Golden Square) is obviously fictional, and evokes the Tiburtine legend of "Hadrian's Golden Carriage" which was supposedly buried somewhere.

Fragments of a relief with hunting scenes and cupids are all that is left of the precious decoration of the Golden Square. Some fragments are in the Vatican Museums: in one there is a goat, a Cupid with a spear and an oak tree with acorns; and in another a deer with a laurel tree behind it, hunting scenes with a lion and a palm tree.
Other fragments have been piled up for decades in a side room of the Golden Square; they deserve to be restored and displayed in the Antiquarium of the Villa.

The octagonal entrance Vestibule with an umbrella dome gives access to a large garden with water basins, surrounded by a double portico with walls decorated with small arches with semi-columns. The floors were in opus sectile of precious marble and polychrome mosaic; the capitals and pilasters of the Corinthian order were in white marble.


The large central exedra at the end (closed to visitors but visible from afar) has seven niches from which jets of water cascaded down into a canal, and then flowed into the garden basins. In the niches there were some sculptures that had been lost and some marbles that framed them remained.

On the eastern side there is a large summer Triclinium: it had a water basin in front and overlooked the panorama towards the Tempe Valley and the so-called "Gladiator's Arena", an oval structure visible in the reconstructive model, of which nothing is known.

The plan of the building is very similar to that of Hadrian's Stoa in Athens, which was home to a library. Perhaps the Golden Square had the same function: the outer portico has a series of niches that could have been used to store papyrus and ancient texts. Given that Emperor Hadrian was very cultured, a lover of study and of the arts, this building could have been the "Cultural Center" of his Villa.