The Pantheon and Ara Pacis

The Ara Pacis

You might not have heard of the Ara Pacis. But you will likely have heard of, or visited, The Pantheon. It’s one of my all-time favourite buildings. There’s something about the sheer scale, and the way it sits so ponderously and immovably, despite the tourists, souvenir vendors, taxis and rip-off restaurants that surround it. There it sits, a monument - nothing has ever deserved the name more. A monument to Agrippa, the great Augustan general; and to Roman engineering. It’s said that even if they tried, it would be very difficult for modern engineers to reproduce the building using the same materials and the same dimensions.

The Pantheon. Solid.

Tourists, tourists, everywhere...

Viewed from the piazza, in the foreground yet another Renaissance fountain and yet another Egyptian obelisk filched by the Romans, the Pantheon remains aloof. With flashes of gaudy red neon from the farmacia to its right, bad electronic music from buskers, twee horse-and-carriage ensembles clopping by -- still the Pantheon retains its dignity. The dignity of almost two thousand years of standing just where it’s still standing. 

Actually, the first iteration of the Pantheon was built between 27 and 25 BC by Agrippa (who died in 12 BC) to celebrate his victory over Antony and Cleopatra in the naval battle of Actium, which was decisive in setting Augustus on his way to becoming the first Roman Emperor. It was built in the Campo Marzio ('Campus Martius' or 'Field of Mars'), and all but traces of that first building are lost - it was destroyed by fire in 80 AD.  One trace that remains, however, is the inscription above the portico: 

M·AGRIPPA·L·F·COS·TERTIUM·FECIT

in full, "M[arcus] Agrippa L[ucii] f[ilius] co[n] s[ul] tertium fecit," meaning "Marcus Agrippa, son of Lucius, made this building when consul for the third time."

Agrippa on the facade.

Columns of The Pantheon portico.

It's the Emperor Hadrian who is most closely associated with the building. He oversaw a complete re-build in the second century AD - Hadrian ruled from 117 to 138 AD. The huge hemispheric dome rises 43.2 metres - the biggest dome ever vaulted in brick. It’s said to be the only edifice from Roman times preserved completely intact. The dome has a central opening, or oculus, of about nine metres diameter, which provides the main light to the interior. It also allows rain - and the occasional fall of snow - indoors. (Wiki argues that it may have been earlier architects who were responsible for the design of the Pantheon, not those of Hadrian).

The Pantheon, so-named because it was originally a temples to a ‘pantheon’ of gods, became a Christian chapel in the middle ages - in 609 AD it was handed to Pope Boniface IV and dedicated as a church to Santa Maria and the Martyrs, which it still is. This dedication probably saved the building from despoilation and destruction through it was stripped of all its bronze. In the 17th century Pope Urban VIII (the Barbarini pope) had bronze from the portico stripped and melted down, mainly for cannons for Castel Sant’Angelo. It is often said that bronze from the Pantheon was used by Bernini to create the famous baldachin above the high altar in St Peter’s Basilica (Wiki disputes this).  Much of the external marble has been filched over the centuries too; and capitals from some of the pilasters are in the British Museum. 

Historic photo of The Pantheon with its "rabbit ears" bell towers.

There used also to be a medieval campanile, or bell tower. Urban VIII had this replaced with twin bell towers, which can be seen in old views of the Pantheon - they were not removed until the late 19th century. They are often attributed to Bellini - and mocked as “rabbit’s ears.”

In more recent times, the Pantheon has been used a mausoleum. The painter Raphael is entombed there, as are two Italian kings. Although Italy has been a republic since 1946, volunteer members of Italian monarchist organisations maintain a vigil over the royal tombs in the Pantheon. You can see them standing silently before the tombs while the tourists mill about. 

Cross-section of The Pantheon's construction.

Of the astonishing construction, Wiki says:

The grey granite columns that were actually used in the Pantheon's pronaos were quarried in Egypt at Mons Claudianus in the eastern mountains. Each was 39 feet (12 m) tall, five feet (1.5 m) in diameter, and 60 tons in weight. These were dragged more than 100 km from the quarry to the river on wooden sledges. They were floated by barge down the Nile River when the water level was high during the spring floods, and then transferred to vessels to cross the Mediterranean Sea to the Roman port of Ostia. There, they were transferred back onto barges and pulled up the Tiber River  to Rome. After being unloaded near the Mausoleum of Augustus, the site of the Pantheon was still about 700 meters away. Thus, it was necessary to either drag them or to move them on rollers to the construction site.

Interior of the dome, with oculus.

The dome of the Pantheon is said to weigh 4535 metric tons, and only stands because of ingenious systems - a honeycomb of hidden chambers and the use of progressively less heavy aggregate. The dome is basically built of concrete resting on eight barrel vaults in the 6.4 metres thick drum wall. From Wiki:

The top of the rotunda wall features a series of brick relieving arches, visible on the outside and built into the mass of the brickwork. The Pantheon is full of such devices – for example, there are relieving arches over the recesses inside – but all these arches were hidden by marble facing on the interior and possibly by stone revetment or stucco on the exterior.

Amazingly, the Pantheon still holds the record for the world's largest unreinforced concrete dome.

Less than a kilometre away is another great Roman dome from the same period -- the Mausoleum of Augustus. The first Emperor was interred there, along with several members of his family. However, it has fallen into sad disrepair, and sits in the middle of Rome, not far from the Tiber, behind a chain-wire fence, overgrown with weeds.

Behind the trees, the fence and the weeds: the great Mausoleum of Augustus.

New home of the Ara Pacis: Richard Meier, architect.

Opposite Augustus's Mausoleum is a bright. white modern new building with high glass walls. The architect was Richard Meier. It encloses the Ara Pacis, or Ara Pacis Augustae (Latin, "Altar of Augustan Peace"). It's an altar dedicated to Peace. Wiki tells us:

The monument was commissioned by the Roman Senate on 4 July 13 B.C. to honour the return of Augustus to Rome after his three years in Hispania and Gaul, and consecrated on 30 January 9 BC by the Senate in celebration of the peace brought to the Roman Empire by Augustus' military victories. The altar was meant to be a vision of the Roman civil religion. It is made up of a small functional altar at its centre, and four surrounding walls; externally, two-tier friezes run along the walls and portray the peace and fertile prosperity enjoyed as a result of the peace brought to Rome by Augustus' military supremacy (Latin: Pax Augusta). 

The Ara Pacis in the Richard Meier building.

But sadly the north-east corner of the Campus Martius, where the original Ara Pacis stood, was a flood plain, and over several centuries it became buried in silt and mud. It was rediscovered in the twentieth century, unearthed, pieced together, and moved. In fact, "the recovery of the Ara Pacis began in the sixteenth century, and finished four centuries later, after many chance discoveries and amazing excavations, with the recomposition of the monument in 1938". (source) Mussolini had a structure built to cover it in 1938, now replaced by the beautiful Meier building. The new building has been controversial, but I think it's a lovely addition in this area.

The original Ara Pacis used to stand between between Augustus’s mausoleum and the Pantheon - they sat in a straight line from each other. The Ara Pacis website paints a fascinating picture of the area almost two thousand years ago:

Strabo, a greek writer, has left us an admiring account of Augustan Rome, which in those days extended between the Via Lata, now the Via del Corso, and the sweeping curve of Tiber. After describing the verdant plain, shaded by sacred groves, and the porticoes, circuses, gymnasia, theatres and temples, which were being built there, Strabo goes on to talk about the sacred area of the northern part of the Field of Mars, sacred precisely because of the existence of the Mausoleum and the ustrinum, in which, in 14 A.D. Augustus' mortal remains were burnt. Between the Mausoleum and the ustrinum there was a sacred grove, full of charming walks. To the south-east, about 300 metres distant from the Mausoleum, rose the Sundial and the Ara Pacis - themselves in fact not described by Strabo - which delimited the area of the plain given over to Augustus' memory.

The ideological urban planning used in the northern part of the Field of Mars only lasted for a short time and within a few decades the integrity of the Sundial was compromised. The level of the land rose relentlessly throughout the area, largely due to the inundations of the Tiber; there were efforts to protect the Ara Pacis by building a wall to halt the process by which the ground level was rising, but obviously these precautions were ineffective in the face of the continual filling in of the entire area. The destiny of the Ara Pacis was therefore sealed and its obliteration irreversible. For more than a millennium silence fell on the Ara Pacis, and the monument was lost even to memory.

The centuries have filled in the whole surrounding area with what we now call Rome's centro storico - the historic centre. But imagine it as open ground, with the Pantheon anchoring one end and the huge Mausoleum of Augustus the other - the 'sacred grove' full of 'charming walks.' They knew how to build in those days. 

Model of the Campus Martius on Augustus's day:
his huge Mausoleum at one end, and a straight road to The Pantheon.
The Ara Pacis is to one side.

View of Augustus's mausoleum today, through the windows beside the
reconstructed Ara Pacis.