Quirinal Dioscuri
Quirinale Obelisk and the Quirinal Diosc

The Quirinal Dioscuri (also known as the Quirinal Horse Tamers) is a colossal marble sculpture group (5.6 m high) in Rome that consists of two nude male figures reining in two horses. It is likely that the colossal Dioscuri on the Quirinal formed part of the decoration of the Baths of Constantine, although they too may have been salvaged from the adjacent temple precinct. Unlike their counterparts, the Capitoline Dioscuri, the horsemen of Quirinal Dioscuri have a dynamic pose and their horses are in motion. 
They remained on the Quirinal Hill in Rome, and gave rise to its medieval name Monte Cavallo. In the late 16th century, Sixtus V had the statues restored, setting them on pedestals with the fountain between them. Under Pius VI the statues were rearranged in the late 18th century, and the one of the obelisks from the Mausoleum of Augustus was set up with them. 
Since the Horse Tamers were among the monuments of ancient Rome never buried, they were immensely influential. Although they have been traditionally identified by their inscriptions as the works of Pheidias and Praxiteles, they are not Greek originals, but date to the Imperial era. The present inscriptions are later additions dating to the time of Sixtus V, perhaps based on Late Antique inscriptions. There have been various interpretations of the two figures and their horses over the course of time. A typically medieval explanation labeled them as two naked philosophers named Pheidias and Praxiteles. In the Renaissance a popular identification for one of the horsemen was Alexander and later the interpretation was expanded to include Philip of Macedon. Since about 1800, they have generally been associated with the Dioscuri, Castor and Pollux.
As the divine saviors and protectors of the city, the Dioscuri were prominently featured on the coins of Maxentius who originally began constructing the Baths of Constantine. There was a long imperial tradition of associating the Dioscuri with imperial heirs. They have been associated with the two sons of Maxentius, which could have been continued under Constantine as his own sons. The statues have also been dating to Severan period.

See also Roman Monuments and Roman Obelisks

"Veduta della Piazza di Monte Cavallo" by Piranesi (1720-1778)


"The Dioscuri on Monte Cavallo" by Maarten van Heemskerck (ca. 1533)

“Quirinal Horse Tamers” (Encyclopedia of the History of Classical Archaeology) by Elizabeth Meaney
“Maxentius, Constantine, and Hadrian: Images and the Expropriation of Imperial Identity” (Using Images in Late Antiquity) by Eric Varner

Quirinal Dioscuri Album (Byzantine Legacy Flickr)

Roman Obelisks Album (Byzantine Legacy Flickr)