part II - the eastern side

~ page 1 ~

The starting point is the end of part I, by Castro Pretorio subway station (line B). As soon as you exit the station, you will find yourselves in front of the National Library; two thousand years ago this rather large area, almost square in shape, became the site of the Castrum Praetorium, an enclosure that Tiberius had built in the early 1st century AD as a permanent camp for the Praetorian Guard, whose task was to act as the emperor's bodyguards.
The Castrum had four gates, one on each side. When the set of Aurelian's walls was built, it joined this structure, which became the north-eastern corner of the city's new boundary.
In the early 4th century Constantine I disbanded the Praetorians; the Castrum was then closed for about one hundred years. During a general restoration program carried out at the beginning of the 5th century, its western side (i.e. the one standing inside the set of Aurelian's walls) was taken down.

the Castrum Praetorium, from a map of ancient Rome
published in 1576; its four gates are not shown,
but old Porta Nomentana (arrow) is featured on the left

the site of the Castrum's northern gate and
(↓ below) a reconstruction of its shape)
As you turn to the right along viale del Policlinico, along the northern side of the Castrum, you will soon come to some small breaches in the wall [map ref. 1]: here are the remains of the original northern entrance to the camp, the Porta Praetoriana, which in time were covered with bricks. From a certain distance (i.e. from the other side of the road) you can easily see how the texture actually changes in this rectangular patch of the wall, above which were three windows, now walled up, likely opened sometimes later.

remains of one of the half columns that supported
the archway of the original Porta Praetoriana
Following the eastern side of the Castrum, we come to a large avenue where the wall faces Rome's main hospital, the Policlinico Umberto I (c.1885), still arranged according to the fashion of those days, consisting of many small individual buildings in Umbertino style, each one for a different medical specialty. Opposite the small kiosk by the hospital's main entrance, a few traces of the eastern gate of the Castrum, the Porta Principalis Dextera, can be faintly told from the texture of the wall. At a certain point the wall makes a round bend; it is impossible to follow its direction because of a small sports ground nearby. So at the first crossing turn right and follow viale dell'Universitą, which runs parallel to the southern side of the Castrum Praetorium. Having been rebuilt in the early Middle Ages, the latter side of the wall is slightly irregular and is not perfectly at square angles with the eastern one.

A few metres or yards further on, you will see again the wall on your right, at the end of via Osoppo. It is useless to walk down this secondary lane, because just round the corner it comes to a dead end, by the gate of a private company's parking lot. At the end of the parking lot, the wall makes a bend almost at square angles; here stands the small gate called Porta Clausa [map ref. 2], unfortunately concealed to the public. Porta Clausa (literally "closed gate") owes its name to the fact of having been walled up already in ancient times. After the Castrum Praetorium enclosure had lost its original function, this gate must have turned into an almost useless passage, and a weak spot in the defensive wall, which represented a waste of armed forces needed to defend it.
So it was obliterated, likely already in late antiquity, as suggested by the use of the same type of bricks the wall is made of for closing the six small upper windows, and was never opened again. The modern buildings built all around the gate during the first half of the 20th century, left free only the outer side of Porta Clausa, which still features the typical white stone facing that emperor Honorius had applied to most of Rome's gates around AD 400 (see further).

↑ above, the outer side of Porta Clausa;
← left, the plaque that remembers the restoration by Urban VIII
(courtesy of Enrico Imperiali)

Near the gate, a plaque topped by a small coat of arms of the Barberini family remembers that in 1628 the wall and the gate itself, in rather bad condition, were restored and consolidated by the will of pope Urban VIII.

Follow viale dell'Universitą until you come to a major crossing with viale del Castro Pretorio. From Porta Clausa up to this spot the wall has vanished. But it can be seen once again on the left, on the very corner of the avenue, by a few Roman fragments hanging from the brick texture.

houses built over the wall in via di Porta Tiburtina
Walking along the inner side of the wall you'll pass by the large Air Force building (on the left); shortly further on, by the crossing with via dei Frentani, it is possible to move again to the outer side.
Note how, due to the rising of the modern street level, the height of the wall along this stretch appears to be considerably low.

We are now approaching the popular district of San Lorenzo. On July 19, 1943, during WW II, this part of Rome was very severely damaged by a heavy bombing; today the neighborhood, with its surviving houses and narrow streets, has a rather decadent though particular atmosphere: most off-site students of the nearby University rent flats or rooms here, so the old spirit of the district has curiously blended with alien modern elements, such as trendy clothes stores, supermarkets, pubs and cafes and even Chinese stores.

As you come by the crossing with via dei Ramni, another short part of the wall is missing, replaced by a modern one with three archways for the local traffic. Immediately beyond this spot, along via di Porta Tiburtina, the ancient wall is once again standing; in the early 1900s private houses were built over it, and windows were opened along its outer side.
Instead on the inner side of this stretch of wall, in a small square, stands the Arch of Sixtus V [map ref. a]: it marks the spot where via Tiburtina, one of the main approaches to Rome from the east, was crossed by the aqueduct called Acqua Felice, opened by pope Sixtus V in 1587 (see Aqueducts, page 3 for more details).

the surviving stretch of Acqua Felice aqueduct (right) ends by the side
of Termini central railway station (left) with the arch of Sixtus V
The arch is now adjacent to the central railway station (Termini), but a short part of the original aqueduct can be seen on the opposite side: these simple arches converge towards Aurelian's wall (hidden by the houses built on it). In particular, you'll notice a pergolato and the uppermost storeys of an aristocratic building dated c.1745 circa, the villa of marquis Gentili, which since 1913 bears the name of its further owner, Gustavo Dominici.
A few metres further, the aqueduct and the wall meet by the site of another ancient gate, Porta Tiburtina [map ref. 3], named after the aforesaid via Tiburtina, which left the city from this spot leading towards the ancient town of Tibur (now Tivoli), about 30 km / 20 mi east of Rome (see the
map of Rome's ancient surroundings). The street in front of the gate is now called via Tiburtina Vecchia, i.e. "old via Tiburtina", as the first part of the modern via Tiburtina no longer follows the ancient direction.

Although Porta Tiburtina is now a ruin, what is left standing is enough to trace its chronological development.
The oldest part is the archway on the inner side: it was built in 5 BC when Octavian Augustus decided to restore the important triple aqueduct that ran by this spot, carrying three water tunnels at different levels (see also Aqueducts): the Aqua Marcia, i.e. the lowest and oldest of the group, the Aqua Tepula, and the Aqua Iulia, that was the highest and uppermost of the three, having been built only 28 years before these works.

the inner side of Porta Tiburtina

When emperor Aurelian had a new set of walls built around Rome, around 275, two semicircular towers were built on the outer side of this archway, thus turning it into one of the city gates, named Porta Tiburtina. Immediately behind the gate was a small inner court; its remains were removed in 1869 (see picture on the right). A house that, meanwhile, had been built there and acted as the excise office for goods entering the city through Porta Tiburtina (picture at the end of the page) was taken down in the early 1900s.

the gate's structure
(see below key to colours)
the aqueduct and the arch (5 BC) ███ 
Aurelian's walls (AD 275) ███ 
stone facing added to the gate (AD 402) ███ 
the towers' alteration (AD 1586) ███ 

the outside of Porta Tiburtina,
covered with the white stone layer
In 402, emperor Honorius had the outer side of the gate reinforced by means of a thick protective layer of white stone set before it; such layer, though, fails to overlap precisely the shape of the the earlier structure, probably due to its hasty making, so the original arch has remained partly visible also from the outside. This side of the gate was also fitted with a portcullis, while the row of five rounded windows above the archway gives light to the chamber where the device was operated. A rough crenellation was also added above the gate, as a shelter for the guards. Finally, the base of the gate, already partly interred (as an inscription says, see further), was freed again from rubble and debris.
the portcullis operating chamber;
one of the three water tunnels
is seen in cross section on the right

The last alteration took place during the late Renaissance, in 1586, when cardinal Alessandro Farnese changed the shape of the towers, giving them a square section. His coat of arms can be seen hanging on the left tower, together with that of another cardinal and, nearby, the one of Sixtus V, who was the pope in those years.

coat of arms of Sixtus V

coat of arms of cardinal Farnese

the outside surface of the original archway of the aqueduct is still
partly visible, as the stone facing added in front of it mismatches its size

On both sides of the gate, the keystone of the old arch is decorated with a cow's head in relief (the one on the outer side is actually a skull). A 13th century chronicle gives a metaphorical explanation of this curious feature:

(...) lo secco čne de fore et significa quelli ke macri intravano in Roma; lo verde oi lo grasso, de dentro, significa quelli ke gessiano grassi de Roma (...)
(...) the bony one hangs outside, referring to the skinny oxen that came into Rome; the young or fat one, inside, refers to the well fed ones that left Rome (...)

Therefore, Rome's legendary wealth (despite the enormous decadence after the fall of the empire) was still believed to have a sort of 'nourishing' effect on those who entered the city. The decoration explains why, since the Middle Ages, Porta Tiburtina has also been referred to as Porta Capo di Bove ("Ox-head Gate"), or Porta Taurina ("Bull Gate").

the ox heads, on the inner and outer sides of the gate
It was also called Porta San Lorenzo because about 800 m / ½ mile east of this spot, along via Tiburtina, stands the basilica of St.Lawrence Outside the Walls; in the past times it was a common custom to name gates after nearby churches, catacombs, or similar places of worship.

inner side: the triple attic with the inscriptions
The attic of the inner side of the gate features three inscriptions (whose letters are now rather faint) that mark the levels of the water ducts. The oldest of the three runs by the uppermost tunnel, the Aqua Iulia, and dates back to 5 BC, i.e. the same time when the arch was built: it mentions emperor Octavian Augustus, crediting him for the restoration of all the aqueducts.
A second inscription follows the bottom level, where the Aqua Marcia flowed, and dates back to AD 79: it was added under emperor Titus, when the same duct was restored.
The last inscription, between the previous two (i.e. along the duct of the Aqua Tepula), refers to a further restoration of the Aqua Marcia, which took place under emperor Caracalla in 212; it also mentions the opening of a long branch called Aqua Antoniniana, which carried water to the newly built Baths of Caracalla.

Instead the outer side features a long inscription carved in the white stone facing, which mentions emperors Honorius and his brother Arcadius, and tells how a large amount of rubble had to be removed in order to free the gate because already in the 5th century debris had piled up by the archway, partly obstructing the passage; as further centuries elapsed, this happened again: the pillars of this gate are now buried so deep in the ground that from the present street level the original archway would almost be too low to walk under even for a man of average height.

the square towers that flank the outer side of the gate

a view of the gate in 1870 (etching and watercolour):
the house used as excise office (left) was still standing