In the Middle Ages, the Torre delle Milizie and the convent of St. Peter and Domenic were built, and above Constantine's building was erected the Palazzo Pallavicini-Rospigliosi; the two famous colossal marble statues of the Horse Tamers, generally identified as the Dioscuri with horses, which now are in the Piazza Quirinale, were originally in this palazzo.
They gave to the Quirinal its medieval name Monte Cavallo, which lingered into the 19th century, when the hill was transformed beyond all recognition by urbanization of an expanding capital of a united Italy.
The healthy[3] cool air of the Quirinal Hill attracted aristocrats and papal families that built villas where the gardens of Sallust had been in antiquity.
In the 18th century, Ferdinando Fuga built the long wing called the Manica Lunga, which stretched 360 meters along via del Quirinale.
In front lies the sloping Piazza del Quirinale where the pair of gigantic Roman marble "Horse Tamers" representing Castor and Pollux, found in the Baths of Constantine, were re-erected in 1588.
Several collections are in this Palazzo, including tapestries, paintings, statues, old carriages (carrozze), watches, furniture, and porcelain.
The present façade was built in 1732–1734 by the architect Ferdinando Fuga on the orders of Pope Clement XII Corsini, whose coat-of-arms, trumpeted by two Fames, still surmounts the roofline balustrade, as in Piranesi's view.