Emperor Constantine I (AD 306-337) is remembered in Rome's history especially for having legalised in the empire the practice of Christian doctrine (313), for having founded the largest among the churches of the city, St.Peter's basilica (c.314-335), but also because in AD 324 he moved the capital of the empire from Rome to Byzantium (presently Istanbul), which was then renamed Constantinople after him. Less known, instead, is the making of a public baths complex he sponsored, as already Agrippa had done before him, as well as Nero, Titus, Trajan, Caracalla, Decius and Diocletian. It was built around AD 315 over the top of the Quirinal Hill, in the heart of the VI Regio (the 6th ancient district), called Alta Semita, once scarcely populated. The size of the Baths of Constantine was not particularly large, especially if compared to the huge ones that emperor Diocletian had built only a few years earlier, whose extension was that of a whole city district; maybe the complex aimed at being more exclusive, for an elite of wealthy citizens.

the Dioscuri and their horses: the main relic from the baths

Both the Baths of Diocletian and those of Constantine drew water from the same source: a branch of the Aqua Marcia aqueduct (for further details see the Aqueducts monograph).

The Baths of Constantine had already been damaged buring the sack of Rome by Alaric (AD 410) and by some fires; but they turned dry, together with the others, in the first half of the 6th century, when during the Gothic Wars the aqueducts were sabotaged and stopped working. So they were soon abandoned and, as well as any other ancient structure, over the Middle Ages they were plundered by whoever needed free construction material: the bricks and the marble that belonged to the baths were taken away even more than the precious statues that adorned their halls.

the Quirinal Hill, from the view of Rome in the Liber Chronicarum Mundi: (from the left) two rotundas that belonged to the baths, the Dioscuri (seen from the back), and one of the two reclining statues now in Capitolium Square

Around the 13th century, one part of the ruins of the Baths of Constantine were included in a stronghold that belonged too the Arcioni family, who also owned other fortified houses, among which the tower that bears their name (see Monti district). When the late medieval chronicles and the early city guides began to mention the baths among Rome's most interesting sites, already very little of the original complex was left standing. One of the earliest graphic depictions of what could be found is featured in the view of Rome in the Liber Chronicarum Mundi, also known as the Nuremberg Chronicle, dated 1493 (left). An identical perspective appears in a similar illustration in the Cosmographia, an atlas of the world published since 1544.

Over the top of the Quirinal two human figures are clearly seen from the back, each of which leads a horse: they are the 'humanized' depiction of the two large statues of the Dioscuri, i.e. Castor and Pollux, the sons of Jupiter, which adorned the complex of the baths. They are Roman copies of Greek original works, but according to a popular belief they were believed to be originals themselves, by the famous Greek sculptors Praxiteles and Phidias, whose names are in fact carved on the respective stands. The third figure on their right is very likely another reclining statue, mentioned further in the page.

remains of the Baths of Constantine (Étienne du Perac, c.1575); a caption by the author says: « Remains of the baths of Constantine on the side looking south-west, wich has no decorations, being badly damaged, but only great walls and halls, especially in the garden of the Honourable Cardinal of Vercelli; after I drew this side, houses and barns were built there, so that today it can no longer be seen, having been covered by such buildings. »		Left to the Dioscuri, instead, stand two surviving rotundas that belonged to the Baths of Constantine. An etching by Étienne du Perac (c.1575, left) features the only considerable part of the ancient structure left standing. In the foreground lies a pile of rubble, below which interesting remains may have still been buried. At the back stands a tall broken exedra (a semicircular hall with an apse), which probably marked the centre of the south-western side of the complex.

Among the notes by Flaminio Vacca, a sculptor and humanist who in 1594 collected some memories about antiquities found in Rome over the 16th century, gives us a brief description of the aforesaid pile of rubble depicted by du Perac some twenty years earlier (on the right). Instead a city map by Leonardo Bufalini (below left), drawn by the middle of the century, features the whole floor plan of the complex, based on the foundations of the ancient building, not covered by new houses yet. Two round halls can be seen on its sides, likely matching the rotundas of the late 1400s illustration.

I remember that where today the Horses of Horse Hill stand, arranged by Sixtus V, was a large heap of stones, mingled with Travertine fragments, which I think was once a Mausoleum, but since it was completely dilapidated, nothing else can be said about it; and it was razed, as can be seen today. Flaminio Vacca, from Memories of several antiquities found in various places of the city of Rome (1594)

By comparing Bufalini's map with a present aerial view of the spot, the size of the baths can be told; they stretched approximately between the present via Nazionale, largo Magnanapoli, and piazza del Quirinale (in the map by Bufalini the Quirinal Palace had not yet been built). Despite the many changes over the following centuries, the main streets of the district still follow the same direction as the ancient ones.


(left) the floor plan of the Baths of Constantine clearly seen in the map by Leonardo Bufalini (1551);
on the right, the same area from a satellite map is shown for comparison: note the similarity of the street plan after almost five centuries

Cartaro's map (1576): the Dioscuri are still facing the remains of the Baths of Constantine, partly replaced by Palazzo Ferrero and by humble houses and barns, as described by E. du Perac's caption; a few years later, in the top left corner the Papal Palace (i.e. the present Quirinal Palace) was built

Around 1510, in the northernmost corner of the ruins, the Ferrero family, who over the century had five cardinals proclaimed among its members, had their mansion built; among the five was Guido Ferrero, one of the most influential clerics of his time, locally known as 'cardinal of Vercelli' (as mentioned in the caption to E. du Perac's etching). Their mansion is clearly seen in the map by Mario Cartaro (left).

Note that, originally, the two Dioscuri did not face north, as they do today, but east, i.e. towards the remains of the baths; their arrangement changed around 1590, when a first fountain was set in the square (see the relevant monograph for details).

By the turn of the new century (1605), cardinal Scipione Borghese started the works for the making of a villa adjoining Palazzo Ferrero, which caused the demolition of the central part of the ruins. Ten years later, the villa was sold to the Altemps family who, in turn, handed it down to cardinal Mazarin in 1641; it is featured as Palazzo Mazzarino in a late edition of the map by Antonio Tempesta (right), in which the Dioscuri appear already turned towards the north, and in front of them stands the first fountain of the square.

Palazzo Mazzarino and, bottom left, the Pope's Palace (i.e. Quirinal Palace), with the Dioscuri in the centre, turned towards the new fountain, are featured in a 1645 edition of Tempesta's map

Finally, in 1704 it became a property of one of pope Clemente IX's nephews, Giovanni Battista Rospigliosi, who was married to a member of the Pallavicini family, whence the name it still bears: Palazzo Rospigliosi-Pallavicini.

Palazzo Rospigliosi-Pallavicini	In 1732 Palazzo Ferrero was replaced by Palazzo della Consulta, the present seat of the Constitutional Court, and the square took its ultimate appearance; but the ancient complex of the baths disappeared almost completely. Then, when the present via Nazionale was opened, around 1875, also the very last ruins of the Baths of Constantine were forever lost. However, a certain number of works that originally belonged to the complex were spared: during the 16th century they were removed to embellish Capitolium Square, whose workshop was in progress.	statue of Costantine, in Capitolium Square

The most important ones are the statues of Constantine and his son Constant II, now standing on the balcony atop the famous stairway by Michelangelo. At the opposite end of the same square, lie two huge allegories of the rivers Nile and Tigris (the latter was turned into the Tiber by altering some details), that Michelangelo used as a front for the double staircase of Senators' Palace (see also Capitolium Square e the Fountains monograph); one of them likely matches the reclining statue seen from the back in the late 1400s illustration previously described. ← the allegory of the Tiber (originally, the Tigris), in Capitolium Square

	the Dioscuri (right), and Palazzo della Consulta in the background ← the statue of Constantine in St.John's porch Another statue featuring Constantine was moved to the porch of the basilica of St. John in the Lateran (left).

But the two main works from the baths, the statues of the Dioscuri, were left on the spot, and still today stand in the centre of Quirinal Square. The two imposing figures have always acted as a landmark of this area: they were mentioned as the marble horses in the 11th century guide Mirabilia urbis Romae and in its following edition in early Italian, Le miracole de Roma (see Language and Poetry for more details). They can also be told in some depictions of the city of Rome dating to the 1400s, that feature the most important monuments. Since the Middle Ages, the top of the Quirinal Hill began to be referred to as Montecavallo ("Horse Hill") because of the two statues, a nickname that gradually became the official name of Quirinal Square, until the late 19th century. the Dioscuri in two views of the Quirinal Hill dating to the 15th century →

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