On the opposite side of the square [5] three diverging streets run straight towards the south, crossing the whole length of the district: together, they form the so-called 'Trident'. The two corners of the Trident are marked by a couple of twin churches, built in the 1600s, when the square was given a symmetrical shape.
The street on the left, via del Babuino (originally called Paolina Trifana, after pope Paul III), is named after a small fountain [6] described in Curious and Unusual, page 2 and Fountains, part II page 2; it leads again to the Spanish Steps.
In the same building by whose corner stands the fountain, in the early 1800s the famous sculptor Antonio Canova had a workshop; after his death, it was taken over by his apprentice Adamo Tadolini, by whom, in turn, it was handed down to his descendants, three generations of sculptors. After the death of the last Tadolini (1967), the atelier, still crammed with many original models, studies and sculptures, was closed; it was reopened in year 2000 and turned into a small museum, with a classy café on the ground floor.

the Fountain of the Artists	Parallel to via del Babuino, just below the Pincio Hill, runs the enchanting via Margutta, a charming street with a high concentration of artist studios housed in the penthouses of the many old buildings, whose peacefulness and silence make a striking contrast with the usual crowd and traffic of this district. Those who know the famous movie Roman Holidays will recognize this street as the one where at no.51 lodges the journalist played by Gregory Peck. Among the non-fictional personalities who lived here are movie director Federico Fellini, painter Renato Guttuso and several others. Here stands Campo Marzio's small district fountain, called the Fountain of the Artists (1927) due to the featured elements: brushes, masks, easels, etc.	the Canova-Tadolini Museum

The central street of the Trident is via del Corso; during the ancient roman age this was the urban stretch of the Flaminian Way, but in the Middle Ages it was renamed via Lata; as of the Renaissance, horse races were held along this street during Carnival, whence the present name, from corsa ("race"). This custom ended in the late 1800s; now via del Corso is Rome's high street.

The third street of the Trident is via di Ripetta, which runs parallel to the river bank. Ripetta [7] (i.e. "small bank") was the name of Rome's minor river port, active since the 1300s, though particularly busy from the early 18th century, when a real wharf, in the shape of large semicircular staircase, was built along the river bank by using large travertine blocks fallen from the Colosseum after an earthquake. In the middle of the staircase was a balcony with a small fountain topped by a lantern.

Unlike the larger port of Ripa Grande (see Rione XII , Ripa), located further south along the river, Ripetta was reached by ships carrying goods especially from the north. The complex was demolished in the early 1900s, due to the works for the making of the large protective walls along the river banks and of a new bridge (Ponte Cavour): the only remains of Ripetta port are the small fountain (now dry) and a column that marked the water level reached on the frequent occasion of floods, both standing in front of Palazzo Borghese (they are featured in Fountains, part III page 18 and in Curious and Unusual, The Floods Of The River Tiber, respectively).

the old Ripetta port (18th century etching by Giuseppe Vasi); the church at the back is St. Jerome of the Illyrians, and further right is the front of Palazzo Borghese

Midway along via di Ripetta, just before the spot where the old port once was, two important ancient roman monuments are found: the Mausoleum of Octavian Augustus [7] and the Ara Pacis (both first half of the 1st century AD).
The former is the enormous tomb built for Rome's first emperor; it consists of three concentric cylinders of different height, covered with earth and with trees growing over it; the innermost and tallest of the three encloses a chamber where the emperor's ashes were kept.

the tomb of emperor Octavian Augustus today	The entrance of the monument was flanked by two twin obelisks, similar to Egyptian ones but carved in Rome, which today stand in other districts (see picture below and Obelisks, page 3). the same monument in a map of 1575, featuring the two obelisks as they stood in ancient times

The Ara Pacis (Altar of Peace) [8], now standing opposite the emperor's tomb, was originally built not far from this spot, along the present via del Corso, to celebrate the peace that followed Octavianus Augustus' victorious campaigns in Spain and Gaul. In front of it stood the obelisk now located in piazza di Montecitorio (Rione III, Colonna), which acted as a sundial and on the emperor's birthday (September 24) threw its shadow in the very centre of the altar. The monument is one of the finest examples of ancient marble carving, as it is covered with reliefs of very high artistic level, some of which portray the emperor himself with members of his family during a ritual procession.
In time the monument collapsed and was buried under the rubble. Some of its fragments were found in the mid 16th century by the foudations of a building in the nearby via del Corso; many others were retrieved between the 19th and the early 20th centuries. A few missing fragments now belonging to other museums, such as the Louvre in Paris, have been replaced by moulds which faithfully reproduce the original parts.

(from the left) the new and rather controversial Ara Pacis complex, and a detail of the frieze on the outer part of the monument
The monument is now housed in a snow-white building designed by the famous American architect Richard Meier, opened in 2006, which triggered a huge controversy for being 'too white, too modern and too bulky' for such a historical context. ...But now it's there!

Palazzo Borghese, the 'keyboard' of the 'harpsichord'	A last noticeable feature along the last stretch of via di Ripetta is Palazzo Borghese [9], the family mansion of the noble Borghese family. It was built here from 1560, and finished in 1610, during the pontificate of pope Paul V, who was a member of this family (Camillo Borghese). Due to its particular shape it used to be known as 'the harpsichord', and its front part was accordingly called 'the keyboard'.	the courtyard of Palazzo Borghese