Santa Maria ad Martyres, also known as the Pantheon, is a 1st century Roman temple that was consecrated as a church in the 7th century. It is at Piazza della Rotonda 12 in the rione Pigna, and is a minor basilica and collegiate church but is not titular or parochial. Pictures of the church on Wikimedia Commons are here. There is a very good English Wikipedia article here.
- 1 Name
- 2 History
- 2.1 Sources
- 2.2 Antecedents
- 2.3 Construction
- 2.4 Original appearance
- 2.5 Pagan cult
- 2.6 Severean restoration
- 2.7 Closure and conversion to church
- 2.8 All Saints' Day
- 2.9 Early middle ages
- 2.10 Later middle ages
- 2.11 Revival of interest
- 2.12 Work on portico
- 2.13 18th century
- 2.14 19th century
- 2.15 20th century
- 2.16 21st century
- 3 Dimensions
- 4 Exterior
- 5 Interior
- 5.1 Layout and fabric
- 5.2 Floor
- 5.3 Dome
- 5.4 Sanctuary
- 5.5 Altars on the right hand side
- 5.6 Altars on the left hand side
- 6 Access
- 7 Liturgy
- 8 External Links
The dedication is to the Blessed Virgin Mary and to all the martyrs of the city of Rome.
The name Pantheon, which means "Temple of All Gods" in Greek, is a nickname now universally used and has replaced the traditional Santa Maria Rotonda. It might have been the original name of the building, but a useful historical corrective is given by this timeline:
Pagan temple in the years 125 to 395: 270 years.
Closed down, no official religious use 395 to 609: 214 years.
Church 609 to 2014: 1405 years.
The edifice has been in use as a church, with the name Santa Maria ad Martyres, for a period over five times as long as its period of use as a temple with the name Pantheon.
The edifice is famous for being, not only a high-status ancient Roman building that has never been a ruin (there are others -see Santi Cosma e Damiano and Santa Pudenziana) but also one that has never been structurally altered. As a result, since the Renaissance it has inspired many writers extolling its architectural virtues as one of the greatest surviving masterpieces of Roman construction.
Hence, it is surprising to find that the surviving ancient documentary sources mentioning it are both few and ambiguous. Our major source is Cassius Dio, consul in AD 229, who wrote that it was called the Pantheon either because it contained statues to lots of gods, or because the dome evoked the empyrean. Further, he asserted that the emperor Hadrian used it as a conference hall, and that the predecessor temple had statues of Julius Caesar and Augustus. These are the only clear contemporary statements concerning the building when it functioned as a temple.
Much of our present knowledge of it depends on analysis of the fabric, and this is still producing new information.
The mediaeval centre of the city is in a meander of the Tiber, and anciently was not a residential neighbourhood. People did not want to get regularly flooded out when they could live on the hills and have water delivered by aqueduct. In early ancient times, this area was undeveloped and was called the Campus Martius or the "Field of Mars", a place where soldiers trained. In the early Imperial period, a closely packed collection of large public buildings such as temples, baths and theatres were built here for the city and the Pantheon was one of these.
The major development was by the emperor Augustus and his cronies, especially Marcus Vipsanius Agrippa who laid out the neighbourhood between 27 and 25 BC. To the south he built the Baths of Agrippa, the first public baths the city had, and to the west dug out the Stagnum Agrippae which was an artificial lake. To the east was a vast colonnaded piazza, the Saepta Iulia. On the site of the present building he provided a predecessor temple just north of an assembly hall called the Basilica of Neptune (remnants of the latter survive).
The archaeological consensus until recently concerning this temple was that it was in the normal Greek style, and faced south to the basilica. This view was promulgated by Rodolfo Lanciani, but Edmund Thomas in his 1997 work The Architectural History of the Pantheon from Agrippa to Septimus Severus via Hadrian promulgated the revisionist view that Agrippa's temple was also a rotunda and faced north. This view is based on recent archaeological evidence.
The temple had to be rebuilt in AD 80 after a massive fire destroyed much of the neighbourhood, and again in AD 100 when it was struck by lightning.
It used to be thought that the present edifice was Agrippa's, because of the large inscription on the frieze of the entablature. This reads: M[ARCUS] AGRIPPA L[UCII] F[ILIUS] CO[N]S[UL] TERTIUM FECIT.
It was also formerly thought that the emperor Hadrian (117-138) had it restored, as this is stated in the Historia Augusta. However in 1892 the architect Georges Chedanne published his examination of the date stamps on the bricks, which concluded rather that Hadrian had completely rebuilt the temple between AD 118 and 125. The inscription naming Agrippa as the builder was simply reproduced -Hadrian was famous for avoiding having his name put on the many monuments that he built. Some scholars then surmised that he designed the building himself.
This conclusion has also been recently revised. Lise E. Hetland published a revisionist summary of the position in the Journal of Roman Architecture in 2007, based on the work of Guey and Bloch, to argue for a beginning of the construction of the present edifice between AD 100 and 115. This would mean that the emperor Trajan was responsible for the project, with Hadrian only finishing the work. A very interesting possibility then arises, that the accession of Hadrian was responsible for the design oddities obvious in the entrance portico and which have puzzled analysts for centuries.
If the original position of the temple entrance was on the south (this is now in dispute), it was moved round to the opposite side so that it faced north. Here the architect (Apollodorus of Damascus?) built a large colonnaded piazza or porticus, a sacred area where people could assemble and sacrifices made. This corresponds neatly to the present Piazza del Rotondo. On the other side, the old Basilica of Neptune was probably turned into a temple library because we have an allusion in a 3rd century papyrus of a Library of the Pantheon.
The surrounding ground level has risen since ancient times. Then, the temple was on a plinth and the entrance was approached by a flight of stairs. Those in the porticus would only have seen the entrance loggia or pronaos looking like a typical temple, with the rotunda hidden from view behind.
The roof was covered with gilded tiles, most likely of bronze, and the walls would have been plastered and painted with architectural details such as pilasters in revetted stonework. Some of these survive on the sides of the portico, but not on the main structure.
How the Pantheon functioned as a religious centre is not clear, and this is another source of scholarly dispute. Some writers claim that Hadrian intended the finished edifice to function primarily as an assembly hall, and only secondarily as a temple.
Its predecessor was apparently built in honour of the emperor Augustus, and hence originally dedicated to the dynastic gods of the Julio-Claudian family: Mars, Venus and Julius Caesar. The meaning of the name Pantheon given to the rebuilt temple seems to have been uncertain in Cassius Dio's day, and this is a very good hint that the religious aspect was not paramount. Some have argued for the building to have had a symbolically religious significance, rather than a cultic one involving sacrifices. That is, the dedication might have been to a single pantheistic deity, Nature or Cosmos, which in a way would have included and given context to all the other pagan Roman deities but would not itself have had a prescribed liturgical programme of worship.
The temple was restored by Emperor Septimius Severus and his son and co-emperor Caracalla in AD 202. They placed a second inscription below the original one. This is now illegible, but it was recorded as reading: IMP[ERATOR] CAES[AR] L[UCIUS] SEPTIMIUS SEVERUS ... ET IMP[ERATOR] M[ARCUS] AURELIUS ANTONINUS... PANTHEUM VETUSTATE CORRUPTUM CUM OMNI CULTU RESTITUERUNT, meaning "Emperor Lucius Septimius Severus... and Emperor Marcus Aurelius Antoninus... carefully restored the Pantheon, ruined by the passage of the years".
It is unknown as to what they actually did, but it is not thought to have been very much.
Closure and conversion to church
The buildng's function as a temple was suppressed in 395, when the emperor Theodosius I ordered the closure of all pagan temples in the Empire. Its function for the next two centuries is unknown, but it is fairly certain that it was used as an assembly hall.
The old notion that a few Goth and Vandal barbarians were able to lay the whole city in ruins in the 5th century is now completely discredited, as is the idea that the popes starting ruling here in the early 4th century. Rather, the city's civic zones continued to function (albeit in disrepair) until the 8th century, and the emperor in Constantinople was recognized as ruler until the same period. The building continued to be held as part of the property portfolio in the city of the imperial government.
However, in 608 Emperor Phocas donated it to Pope Boniface IV so that it could be turned into a church. Hence it was consecrated and dedicated to Our Lady and all the martyrs in the following year, 609, after the surviving pagan statuary ("the pagan filth") was thrown out. A grateful Roman senate ordered the erection of a surviving memorial column in the Forum to the honour of the emperor, which happens to be the last act on record that it performed.
All Saints' Day
Traditionally the consecration was on 13 May, which was then celebrated as the feast-day of all Roman martyrs not specially celebrated by name. Pope Gregory III (731-41) consecrated a chapel with the same dedication at the old St Peter's, and this was the origin of the 1 November date. The 13 May celebration was suppressed, but it is still kept in this church as the dedication date.
Later, this was extended to all unknown saints and so came about the solemnity of All Saints.
Further, Pope Boniface was said to have brought thirty-eight (or twenty-eight) cartloads of martyrs' remains from the catacombs and enshrined them in the church. It is now considered that this delivery was in the reign of Pope Gregory IV (828-44), who re-dedicated the church at a time when the catacombs were being stripped and abandoned.
Early middle ages
In 663 Emperor Constans II visited Rome and, according to Peter the Deacon, looted the monuments of the city of their surviving bronze artefacts. Here, the gilded bronze tiling of the roof (which was wholly decorative, as the dome is watertight) was stripped off. A later story has it that the consignment was stolen by pirates (anachronistically described as "Saracens") near Syracuse while it was being shipped to Constantinople.
Pope Gregory III had the dome reclad with lead in 735.
At this stage, the surviving population of the city was settling on the lower regions where water was fairly easily available from shallow wells and the river. The great edifices of the Campus Martius were squatted, and all the open spaces in the river's meander filled with houses except the Stadium of Domitian, now the Piazza Navona. There was no piazza in front of the church when this process was finished, only a narrow street, and the edifice apparently had domestic structures built against it on all sides except the front.
The Church in Rome had a massive re-organization of its facilities for worship in the 10th and early 11th centuries, which is not well documented. Before then, the local parish church was the basilica of San Lorenzo in Damaso, but dozens of little parish churches were subsequently built. Also, this church was made parochial in the 10th century and remained so for almost nine centuries.
Later middle ages
The fact that the building was fireproof and had only one doorway meant that it made a very good bunker in times of trouble. In 1087, a character called Guibert was elected anti-pope as Clement III in opposition to Gregory VII, and he and his supporters held out in here for thirteen years until his death in 1101. The same thing happened again in 1101 with an anti-pope called Sylvester III. So, in 1153 Pope Anastasius IV built a palace next to the church (the left hand side, apparently) so as to keep control of it.
In 1270, a campanile was added to the portico and an epigraph celebrating the event survives by the entrance. Depictions survive of this structure, which had two storeys. The first was a blank brick cube placed just behind the tip of the pediment, and the second was another cube with two double arched soundholes on each face. There was a pyramidal tiled cap.
At some unknown date the three columns at the left hand end of the portico were robbed, and replaced with the walls of a house inserted into that end. The destination of the pillaged columns seems unknown as well.
In the Babylonian Captivity, the period when the papacy was based at Avignon in France, (1309-1377), the city entered the lowest point in its entire history. The population fell below 20 000 as the local nobility terrorized the population and indulged in gang warfare. The church was desecrated, and turned into a fortress during a feud between the Colonna and Orsini families. Its portico was employed as a poultry market, and the scars on the columns of the portico are attributed to the supports for its stalls. (It is not known when the market actually started.)
With the return of the popes from Avignon to Rome, the church was restored to use. In 1418 Pope Martin V began the process of civic enhancement of the edifice, and this was continued by Eugene IV in 1435. This entailed the clearing away of the houses stuck to the rotunda on the right hand (west) side, and also demolishing those in front of the church to create a piazza. The houses on the left hand side were left. Unfortunately, the portico and piazza then continued to be the location of the above-mentioned market which continued until the 19th century.
The house within the portico could not be demolished because its walls were holding the left hand end up in lieu of the three missing columns.
A sketch of the church at the end of the 15th century is here. Note that there is a cross on top of the dome. Was the oculus blocked then? This would have made the church very dark.
Revival of interest
The Renaissance saw the building become the focus of admiration, and the beginning of a steady supply of laudatory descriptions. For example, an English traveller called William Thomas wrote in 1549 that it was the "perfectest of the antiquities". In 1520, Raphael was buried here and, although the tomb was lost to view for some time (to be rediscovered in 1833), other great artists such as Annibale Caracci and Taddeo Zucchero followed his example. Also, the fifteen altars started to be adorned with high quality altarpiece paintings in this century.
The Confraternity of the Virtuosi at the Pantheon was a confraternity of artists and musicians that was founded here by a 16th century Canon of the church, Desiderio da Segni, to ensure that proper worship was maintained in the chapel of St Joseph and to foster artistic and cultural activities. The first members were, among others, Antonio da Sangallo the younger, Jacopo Meneghino, Giovanni Mangone, Taddeo Zuccari, Domenico Beccafumi and Flaminio Vacca. The confraternity continued to draw members from the elite of Rome's artists and architects, and among later members we find Gian Lorenzo Bernini, Pietro da Cortona, Allessandro Algardi and many others. The institution still exists, and is now called the Academia Ponteficia di Belle Arti (The Pontifical Academy of Fine Arts), based in the palace of the Cancelleria.
Pope Pius IV repaired or recast the ancient door in 1563. There is doubt as to whether this door belongs to the ancient building, as it seems not to be properly fitted to the doorcase.
Work on portico
Pope Urban VIII (1623-1644) replaced one of the missing granite columns, the first in the absent row, and had his coat-of-arms carved in the capital. On the other hand, he also stripped out the bronze ceiling of the portico and used most of the metal to cast cannon for the Castel Sant'Angelo (the assertion that some of it went into the baldacchino of the new St Peter's seems to be an urban legend).
He also ordered the mediaeval campanile to be demolished and replaced by two campanili built on top of the rectangular entrance block, which were allegedly designed by Bernini. These were two identical cubical kiosks each having four single open arches, and with a slightly ogee square cupola. They survive in many depictions, as they were only removed in 1883. Many Romans found them ridiculous, giving them the nickname "donkey's ears", but apparently they weren't Bernini's fault.
The two other columns missing on the left side were finally replaced by Pope Alexander VII (1657-1667). He used columns in red granite found in the Baths of Nero near San Luigi dei Francesi, and also put his coat-of-arms in the capitals. These three replacement columns are obvious, because their capitals are much crisper than the eroded ancient ones of the others.
The other major intervention by Pope Alexander was to lower the level of the piazza outside. As mentioned, the edifice when newly built had been approached by a short flight of steps but the ground level had risen so much that the entrance was now below ground level. The work left the floor of the portico level with the piazza, as it still is.
In 1668, Pope Clement IX inserted railings in between the portico's outer columns with a lockable gate, which finally put an effective stop to market traders erecting their stalls in the portico.
Pope Innocent XI (1676-1689) had the roof of the portico repaired, leaving it tiled which it still is.
In 1749 there was a major restoration of the polychrome marble interior wall decoration, which was done to a different design to the ancient one it replaced. This was done by Paolo Posi. This has been violently criticized since, but the new design was judged to be more aesthetically pleasing at the time -and there is a suspicion that the little porphyry pilasters removed were wanted for use elsewhere (has anybody tried to track them down?).
A major re-ordering of the parishes of the Centro Storico took place in 1824, under the bull Super Universam issued by Pope Leo XII. This suppressed the ancient parish attached to the church.
After the conquest of Rome by Italy in 1870, the Italian government took over the responsibility for maintenance. In 1873 the floor was restored in a way faithful to its original design. The buildings hugging the right hand, western side of the church were finally demolished to create the present Via della Rotonda. The 17th century iron railings were removed from the portico, but was replaced by a railing fence which enclosed that part of the piazza nearest the portico.
The quid pro quo was that the church was to become a nationalist shrine. It was the burial place of King Victor Emmanuel in 1878, one of the chapels being destroyed for his memorial. His son King Umberto was similarly interred in 1900. The two royal tombs are maintained by the "National Institute of Honour Guards to the Royal Tombs", founded in 1878. They also organize picket guards at the tombs, selected on a voluntary basis. This is actually quite controversial in modern republican Italy, but the royalist faction is itself now too much of a relic of history to be a threat to the establishment any longer.
The building is in the care of the Soprintendenze, the archaeological authorities. In the 1930's they proposed to restore the interior decoration to its ancient appearance, and did so to a small section of the wall as a demonstration. This project would have been extremely expensive, and was not followed through. Outside, the 19th century railing fence was removed and the piazza tidied up so as to acquire its present appearance.
There has recently been a major restoration and cleaning program.
In 1929 the church was made the seat of the Military Ordinariate of Italy, but this has now transferred to Santa Caterina a Magnanapoli. In 1984 a college of twelve secular canons was set up, which in 1991 was put under the ultimate authority of the Cardinal Vicar. This is formally delegated to the Archbishop of the Military Ordinariate, which hence has immediate responsibility for the church.
In December 2017, a new gilded bronze high altar "pro populo" was provided. The sculptor is Federico Severino.
In the same month, it was finally agreed that admission was to be controlled. Entry was to be by ticket, except for liturgical events. The charge was to be two euros.
in 2018, as well as the twelve serving canons, the college had a further three honorary members.
Width 34m, length 20m.
Columns: shaft height 11.8m, capital height 2.4m, width at shaft base 1.48m
Internal diameter 44.4m, height ditto, wall thickness at base 6m, diameter of oculus 8.8m
Layout and fabric
The building consists of three separate architectural elements. The main part is a circular hall or rotunda into which the hemispherical dome is inserted. In front there is a pronaos or portico in the form of a Greek temple, and this is joined onto the rotunda by means of a large rectangular flat-roofed block.
The fabric of the walls is in brick and Roman concrete, with the dome in concrete only.
The large entrance portico contains sixteen monolithic granite columns of the Corinthian order, the shafts of which are about 12.5 metres high and 4.5 metres round. Originally eight were of grey granite, and eight of pink with capitals and bases in white marble. These were extremely high-status items in ancient times, and their cost must have been enormous. Back then, transport was expensive -and the columns were brought all the way from Egypt. Further, the grey ones came from a quarry in the Eastern Desert called Mons Claudianus, and had to be dragged to the Nile river before being put on boats. The pink ones came from Aswan, and are of the same stone as the ancient Egyptians used in their architecture.
There are eight columns at the entrance (this arrangement is known as octostyle), and these support an entablature and a triangular pediment. The first, third, sixth and eighth columns have rows of two columns each behind them, forming three aisles in the portico. The wider central aisle leads to the entrance, while the side ones lead to two enormous semi-circular niches in the rectangular block. These are thought to have contained statues of Agrippa and Augustus.
As mentioned, the three columns at the left hand side of the portico are not original, but came from the Baths of Nero.
The inscription on the architrave reads: M AGRIPPA L F COS TERTIUM FECIT, meaning "Marcus Agrippa son of Lucius built this while consul for the third time". The tympanum of the pediment above is now blank, but analysis of the pattern of surviving clamp holes indicates that it used to have a bronze device featuring an eagle within a wreath with ribbons.
If you look round both sides of the portico, you will see surviving, badly weathered remains of the original exterior decoration which here features a pair of ribbed Corinthian pilasters attached as revetments connected by two friezes featuring swags.
Inside, the portico now has no ceiling except for a short barrel vault with a single line of coffering over the door. The ceiling used to be bronze, possibly chased with decorations and gilded, before it was looted in the 17th century. Chedanne has suggested that the entrance arch was continued by a bronze barrel vault to the entrance colonnade.
It used to be thought that the bronze was taken in 1632 to be used by Bernini for the columns of the canopy above the high altar of St Peter's. The surplus, after Bernini had finished, was then used for cannons at Castel Sant' Angelo. Work done from Vatican archive documents have led to the conclusion that cannon is what most of it became, with little if any finding its way to Bernini.
The arched bay before the entrance has sculpted marble slabs on its side walls, featuring pagan priestly symbols and sacrificial instruments. The side door in the left hand side is the entrance to rooms once used by the Confraternity of the Virtuosi (mentioned above), as well as the access to a staircase leading to the roof.
The bronze doors are among the few ancient ones that have survived; they are, however, heavily restored and there is a suspicion that they did not originally belong to this building.
A design problem
The design of the pronaos raises a problem that has exercised analysts since the 16th century. It is not easy to see from the street, but over the roof of the portico the front wall of the rectangular entrance block has a triangular motif like a ghost pediment, the same size as the real one below. Further, the proportion between the size of the pediment and its height from the ground is incorrect according to the canons of Classical architecture.
The reason for this seems to be that the columns used were too short for the initial design. The suggestion that the pronaos was added to the original rotunda as a separate project is now disproved, so something went wrong during construction. One suggestion is that some or all of the original set of longer columns were lost in shipwreck on their way from Egypt, but a more interesting suggestion derives from the new date of construction which puts its beginning in the reign of Trajan and its completion in that of Hadrian. The speculation is that Hadrian diverted the longer columns to use them in the temple that he built to his deified predecessor and his wife, Trajan and Plotina, which used to stand in the Forum of Trajan.
The rotunda drum is a very solid construction, with a massive wall which is six metres thick in order to provide support for the dome. The area was marshy before the ancient city spread into it, and so there was a danger for the designers that the building would have started sinking on completion. So, the foundation is a solid ring of concrete 7.3 metres wide and 4.5 metres deep. On this is the cylindrical wall of the rotunda, made of three superimposed sections divided by two projecting stone string courses that run all the way round. In each section or storey is an arcade of brick relieving arches embedded in the concrete.
However, the rotunda drum wall is not solid concrete and brick. Apart from the weight of the dome, there was another problem that the original architects had to face -and that was the fact that Roman cement was exothermic. In other words, as it was setting it was giving off heat, so when it cooled it contracted and was liable to crack. To obviate this possibility, the structure contained a series of voids as well as the brick arches. Eight large internal niches break the rotunda into eight gigantic piers, and in each of these there is a semicircular room at ground level with a tiny passage connecting it to the outside (because of the shape on the plan, these are called “key chambers”). Also, there was an internal corridor above the above-mentioned internal niches, and you can see the windows giving light for this in the interior layout.
Another design feature intended to avoid stress cracking was that the aggregate in the concrete gets lighter with height, and the same feature applies to the dome. The lower walls have fist-sized chunks of tufa and travertine limestone, but grades into brick before becoming small bits of tufa and pumice in the upper part of the dome.
The dome is meant to be appreciated from the inside. Externally, it does not feature on the city's skyline because it appears as a shallow saucer despite being hemispherical. The reason for this is that it needed to be buttressed externally; this was only worked out relatively recently, and the analysis is to be found in Mark & Hutchinson: On the Structure of the Roman Pantheon, Art Bulletin 68, 1 (1986).
From the outside, you need to be aware that the springing of the dome starts at the level of the second string course or two-thirds of the way up the wall. The upper third of the wall supports a series of seven concentric brick rings resting on the dome. The problem these address is that the weight of the dome is forcing its lower part outwards, and so causing radial cracks. These were noticed in the 1930's. The ring buttresses are there to provide downward thrust, and so stop the dome creeping outwards and destroying itself.
In the same analysis, it was shown that the internal coffering has no structural function. Any lightening of the structure that it causes is not relevant to its stability.
How the dome was built is an ongoing focus of debate. Many modern writers presume that it was cast in one piece, but some thought given to the wooden shuttering that would have been needed has cast doubt on this. An alternative idea is that the dome was cast in sectors, with the shuttering being moved around the centre point as needed.
The dome was originally covered with gilded tiles, thought to be bronze although the original documentation does not specify this. This covering was looted by Emperor Constans II in 663. However, the oculus keeps its original bronze lining.
Basilica of Neptune
The rotunda is now isolated from the surrounding buildings, but in ancient times this was not the case. At the back, and just touching, was a large transverse hall known as the “Basilica of Neptune” and, if you go round to the back of the rotunda, you can see its remains. The Via della Palomba now runs through it, but it used to have a cross vault of three bays. What you can see now is a large brick wall with an apse framed by a pair of Corinthian columns, and a frieze with dolphins and tridents.
It is thought that this was the library of the Pantheon when it was functioning as a temple. There was no connecting door between temple and basilica.
Layout and fabric
The interior never fails to have an impact on visitors. On entering, you find yourself in a large circular space dominated by the dome. The wall has two architectural orders or storeys, separated by a deep first entablature while a second narrower entablature runs underneath the dome. The attic between the entablatures was the part of the interior re-ordered in the 18th century.
Facing the entrance is a large semi-circular exedra or apse, which is higher than the first entablature and so has this running round its inside. It is preceded by a pair of Corinthian columns in pavonazzetto marble. To each side are three other exedrae, the two central ones being semicircular also but the four diagonally placed ones being rectangular. The first entablature runs over the top of these exedrae, being supported by a pair of ribbed Corinthian columns in each and with a pair of engaged square pilasters in the same style at the corners. The semicircular exedrae have these in pavonazzetto marble like the main apse, while the rectangular ones have giallo antico from what is now Tunisia. The semicircular ones contain one statue niche each, while the rectangular ones have three. This indicates that the semicircular ones were for higher status gods.
In between the exedrae are a total of eight aedicules or shrines built against the wall, comparable in style to the altars of Baroque churches. Each has a pair of small columns in giallo antico, porphyry or granite supporting a pediment that is either triangular or segmental. The triangular ones flank the entrance and apse. The design of the polychrome marble wall cladding surrounding these is original, being in opus sectile (geometric patterns of large coloured marble tiles in different shapes and sizes). However, many of the tiles are replacements; it is estimated about half.
There used to be a total of fourteen side altars and chapels in here, one in each of the aedicules and exedrae, but two were ejected to make way for royal tombs.
The small niches in the exedrae obviously once held statues of gods. After the 18th century restoration some of them held memorial portrait busts, mainly of the members of the Virtuosi. This tradition started in 1766, but was brought to an end by Pope Pius VII who moved the busts to the Protomoteca Capitolina, which he had founded in 1820.
Above the first entablature, the attic contains large rectangular apertures lighting the internal corridor within the wall. The 18th century restoration left these with small floating triangular pediments, and separated them by blank square panels with decorated stucco frames. The original décor was known from illustrations, and has been replicated in a section of the attic. It can be seen that the original scheme was much more fiddly, involving an attic plinth on which little porphyry Corinthian pilasters in shallow relief stood, four between each aperture. The wall surface between these had polychrome marble cladding similar in style to that around the aedicules.
A modern set of Stations of the Cross in bronze has been provided, sculpted by Federico Severino.
The floor can be regarded as original; although heavily restored in 1873, the design and materials were faithfully reproduced. It has 89 squares, ordered from the entrance in one row of three, one of seven, two of nine, three of eleven, two of nine, one of seven and one of three. The pattern consists of alternate smaller squares and circles within the squares, focusing on a circle right at the centre under the oculus which is actually a drain for rainwater falling down. The floor slopes slightly towards this so as to avoid puddles.
The stones used are granite, porphyry, pavonazzetto and giallo antico to match the wall claddings and columns.
The magnificent dome, a monument to the Roman invention of concrete and architectural skill, creates a unique sense of space in the building, and the simple decorative scheme emphasizes the architectural perfection.
This coffered dome has a diameter of 43.30 meters, which means that it's the largest masonry dome ever built -in fact wider than the dome at St Peter's, but not as big in volume (the latter is elliptical). No matter what its size is relative to other domes, the fact that it covers the entire hall gives it more impact than domes that cover only part of a larger building -it encloses the viewer in a special way.
The height from the floor to the middle of the dome (actually, where the middle of the dome would have been had it not been open as an oculus) is also 43.30 meters. So, famously, if you continued the curve of the dome to form a sphere the latter would just touch the floor.
The cassettes of the coffering number twenty-eight in each of five concentric circles, obviously getting smaller as they approach the oculus. Each cassette or coffer recesses in three steps, and the central panel is thought to have been originally painted blue with a bronze star.
The oculus provides the only natural light and air for the church once the door is shut.
The high altar and the apse were rebuilt by Pope Clement XI (1700-1721). The altar was designed by Alessandro Specchi. In the apse, a copy of an icon of the Madonna in the Byzantine style is enshrined. The original, now in the Chapel of the Canons at the Lateran, has been dated to the 13th century, although tradition claims that it is much older. The apse painting, Glory of all the Saints, was painted in 1544 by Giovanni Guerra.
In May 2018, a new gilded bronze high altar "pro populo" was consecrated. The sculptor is Federico Severino. This is a very impressive high-relief work, depicting a scene from the Book of Revelation featuring the Lamb of God and the Martyrs Clothed in White. The work matches the Stations of the Cross and the ambo, by the same artist.
The altars and chapels are described in anticlockwise order, starting from the right of the entrance.
Altars on the right hand side
Altar of St Nicholas
The first aedicule altar on the right is dedicated to St Nicholas of Bari, and has as its altarpiece a canvas depicting The Madonna of the Girdle and St Nicholas, painted in 1686 by an unknown artist.
Chapel of the Annunciation
The first exedra chapel on the right is the Chapel of the Annunciation, which has a fresco of the Annunication attributed to Melozzo da Forli or Antoniazzo Romano. The marble angels are 17th century. On the left hand side wall is a canvas by Clement Maioli, St Lawrence and St Agnes, painted 1645-1650. On the right hand side is a canvas from 1633, The Incredulity of St Thomas, by Pietro Paolo Bonzi.
When this was a parish church, the baptismal font was situated here.
Altar of Our Lady, Queen
The second aedicule altar on the right is dedicated to Our Lady, Queen of Heaven, and has an anonymous 15th century work of the Tuscan school The Coronation of Our Lady.
Tomb of King Victor Emmanuel II
The second exedra chapel, formerly dedicated to the Holy Spirit, is now the tomb of King Victor Emmanuel II (died 1878). A competition was held to decide which architect should be given the honour of designing it. Giuseppe Sacconi participated, but lost -he would later design the tomb of Umberto I in the opposite chapel, as well as the Vittoriano. Manfredio Manfredi won the competition, and started work in 1885. The tomb consists of a large bronze plaque surmounted by a Roman eagle, and the arms of the house of Savoy. The golden lamp above the tomb burns in honour of Victor Emmanuel III, who died in exile in Alexandria, Egypt in 1947.
Altar of St Anne
The third aedicule altar has a sculpture by Lorenzo Ottoni of St Anne with Our Lady.
Chapel of Our Lady of the Railing
In the third exedra chapel on the right is a 15th century painting of the Umbrian school, The Madonna of Mercy between St Francis and St John the Baptist. It is also known as the Madonna of the Railing, because it originally hung in the large niche to the left-hand side of the portico, where it was protected by a railing. It was moved to the Chapel of the Annunciation, and then to its present position some time after 1837. A bronze epigraph commemorates Pope Clement XI's restoration of the sanctuary.
On the right wall is a depiction of Emperor Phocas presenting the Pantheon to Pope Boniface IV, painted in 1750 by an unknown artist.
Three memorial plaques are placed in the floor, the one commemorating a Gismonda written in the vernacular.
Altar of St Cecilia
Altars on the left hand side
Altar of St Athanasius
The fourth and final aedicule altar on the left hand side has a statue of St Athanasius, made in 1717 by Francesco Moderati.
Chapel of the Crucifixion
The third exedra on the left is the Chapel of the Crucifixion, where you can see the Roman brick wall with three niches for statues of minor gods. The wooden crucifix on the altar is from the 15th century. On the left wall is a canvas by Pietro Labruzzi, Descent of the Holy Ghost, from 1790. On the right side is the low relief Cardinal Conslavi presents to Pope Pius VII the five provinces restored to the Holy See, made by the Danish sculptor Bertel Thorvaldsen in 1824. The bust is a portrait of Cardinal Agostino Rivarola (died 1842).
Altar of Our Lady of the Rock, and Tomb of Raphael
The third aedicule altar on the left is dedicated to Our Lady of the Rock. It holds the mortal remains -Ossa et cineres ("Bones and ashes"), as the inscription on the sarcophagus says -of the great artist Raphael. His "official" fiancée, Maria Bibbiena, is buried to the right of his sarcophagus. She was the niece of Cardinal Bernardo Dovizi, and died before she and Raphael could marry -if he ever wanted to to go that far (possibly not, as he seems to have been more interested in Margarita Luci).
The sarcophagus was given by Pope Gregory XVI, and its inscription reads ILLE HIC EST RAPHAEL TIMUIT QUO SOSPITE VINCI / RERUM MAGNA PARENS ET MORIENTE MORI, meaning "Here lies Raphael, by whom the mother of all things (Nature) feared to be overcome whilst he was living, and whilst he was dying, herself to die". The epigraph was written by Pietro Bembo. The present arrangement dates from 1911, and was designed by Antonio Muñoz. The bust of Raphael is by Giuseppe Fabris, sculpted in 1833.
The two side plaques commemorate Maria Bibbiena and Annibale Caracci. Above the tomb is the statue known as the Madonna del Sasso, (Madonna of the Rock), so named because she rests one foot on a boulder. It was commissioned by Raphael, and sculpted by Lorenzetto in 1524.
Tomb of King Umberto I
The tomb of King Umberto I and his wife Margherita di Savoia is in the second exedra chapel on the left, opposite that of his father. The chapel was originally dedicated to St Michael the Archangel, and then to St Thomas the Apostle when it had an altarpiece of the saint by Pier Paolo Bonzi.
The present design is by Giuseppe Sacconi, completed after his death by his pupil Guido Cirilli. The tomb consists of a slab of alabaster mounted in gilded bronze. The frieze has allegorical representations of Generosity, by Eugenio Maccagnani, and Munificence, by Arnaldo Zocchi. The altar with the royal arms is by Cirilli.
Altar of St Agnes
The second aedicule altar on the left hand side has a statue of St Agnes, by Vincenzo Felici. The bust to the left is a portrait of Baldassare Peruzzi, derived from a plaster portrait by Giovanni Duprè.
Chapel of St Joseph
The first exedra chapel on the left is the Chapel of St Joseph in the Holy Land, and this was also the chapel of the Confraternity of the Virtuosi at the Pantheon. The altar is embellished with false marble. On the altar is a statue of St Joseph and the Holy Child, by Vincenzo de Rossi. To the sides are paintings by Francesco Cozza, one of the Virtuosi: The Adoration of the Shepherds on the left side, and The Adoration of the Magi on the right. Both were painted in 1661. The stucco relief on the left side, the Dream of St Joseph is by Paolo Benaglia, and the one on the right side, Rest During the Flight from Egypt is by Carlo Monaldi. On the vault are several 17th century works, from left to right: The Cuman Sibyl by Ludovico Gimignani; Moses by Francesco Rosa; The Eternal Father by Giovanni Peruzzini; David by Luigi Garzi and finally The Eritrean Sibyl by Giovanni Andrea Carlone.
Altar of the Assumption
You are now back at the entrance.
The opening hours are (church website, June 2018):
Weekdays 8:30 to 19:30, Sundays 9:00 to 18:00, secular public holidays 9:00 to 13:00.
Since the church's opening arrangements are administered by government employees, it is closed on New Years Day, May Day and (very oddly) on Christmas Day.
If you go here early in the morning, just after it has opened, you'll be able to enjoy the building without the background noise of hundreds of tourists -this makes it easier to appreciate that it is, in fact, a church. Otherwise, the best time to visit is on a rainy day in winter. The raindrops falling from the oculus give an impressive show.
If you are in Rome in winter and it starts to snow heavily (a rather rare event), try to get in here. The snowflakes falling inside are really spectacular.
An admission charge of two euros was agreed upon in December 2017, and was to be implemented in 2018.
The only Masses celebrated here weekly are for Sundays and Solemnities, according to the church's website (June 2018). There are two, one on Saturday as the vigil at 17:00 and one on Sunday at 10:30.
There is a famous and spectacular celebration of Mass on Pentecost, when rose petals are tipped through the oculus (these might be replaced by bits of other flowers nowadays).
The Dedication of the Church is celebrated on 13 May, and Pope St Boniface IV on the first Sunday after 25 May.
Masses are also held on other special occasions, such as the Feasts of the Ascension and Assumption which were traditionally celebrated with great solemnity here, but most of the time the church is treated like any other ancient monument. Its true status is hardly noticed by most visitors, and their behaviour inside can be offensive owing to ignorance.
Rather oddly, this is not a titular church.