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Internal Dome of Pantheon

Internal Dome of Pantheon


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Interior of the Pantheon, Rome, c. 1734

In Panini's day, as in our own, the Pantheon was one of the great tourist attractions of Rome. Built under Hadrian in the 2nd century, this monumental domed temple has survived intact, owing to its consecration as a Christian church—Santa Maria Rotunda—in AD 609. Panini's depiction is populated with foreign visitors and a lively mix of Romans from all social strata who congregate in the Pantheon to pray, to chat, and to admire the wondrous architecture.

Trained in architecture and theatrical design, Panini manipulated the perspective to show a larger view of the interior than is actually possible from any single place. The viewpoint is deep within the building, facing the entrance. The portals open to the colossal columns of the porch and a glimpse of the obelisk in the piazza before the church. Through the oculus in the center of the dome, Panini revealed the bright blue sky flecked with clouds.

As Canaletto was to Venice, so Panini was to Rome. Both artists documented with exacting skill and vibrancy the monuments of their cities and the daily comings and goings of the inhabitants. In this case, Panini depicted the classical landmark that inspired the design of the Rotunda in the National Gallery's West Building.

More information on this painting can be found in the Gallery publication Italian Paintings of the Seventeenth and Eighteenth Centuries, which is available as a free PDF https://www.nga.gov/content/dam/ngaweb/research/publications/pdfs/italian-paintings-17th-and-18th-centuries.pdf

Inscription

on the collar of the dome: [LAVDATE] DOMINVM IN SANCTIS EIVS LAVS EIVS IN ECCLE[SIA SANCTORVM]

Provenance

The Dowager Countess of Norfolk[1] (Christie, Manson & Woods, London, 20 November 1925, no. 69) bought by (William Sabin, London)[2] sold presumably by him to (Count Alessandro Contini Bonacossi, Rome) purchased October 1927 by Samuel H. Kress [1863-1955], New York[3] gift 1939 to NGA.

[1] Oral communication from Charles Beddington, Christie's, 17 March 1993.

[2] Art Prices Current, n.s. 5 (1925-1926): 29, no. 618.

[3] The bill of sale for sculpture, maiolica, furniture, antique velvet, and several paintings, including NGA 1939.1.24, is dated 5 October 1927 (copy in NGA curatorial files). The Panini was the first non-Renaissance Italian painting acquired by Kress (see Edgar Peters Bowron, "The Kress Brothers and Their 'Bucolic Pictures': The Creation of an Italian Baroque Collection", in A Gift to America: Masterpieces of European Painting from the Samuel H. Kress Collection, Exh. cat. North Carolina Museum of Art, Raleigh, 1994: 43, fig. 2).

Associated Names
Exhibition History
Technical Summary

The support is a fine, plain-weave fabric. The ground is a reddish terracotta-colored layer that contains large aggregates of translucent white pigments. It is exposed in the spandrels of the arched top. In the top third of the composition a warm gray-brown layer was applied over the ground in the bottom third, under the floor, there is a cooler, lighter gray layer over the ground. In the ceiling the red tone of the ground remains visible as highlights in the floor it remains visible at the edges of the figures to set them off and soften the transition from the dark clothing to the lighter floor. The gray underlayer is similarly used as shadowing around the eyes of the figures.

Using a straightedge, lines were incised into the gray-brown layer as guides for the placement of the coffers in the ceiling similar lines were also used to place the floor tiles and set the perspective. A stylus was used to define the contour of the coffered ceiling. Only the letters in the inscription seem to have been incised into the wet paint freehand. The composition appears to have been sketched in before the lines were incised and the paint applied: the incised floor lines stop precisely at the edges of some of the figure groups. This careful planning seems to have eliminated the need for significant alteration in the painting process. Artist's changes are limited to the sculptures in the niches and to the position of the font to the left of the doorway. Several figures, however, such as the monk in a white cowl at left center, were painted over the floor designs, revealing that some changes were made late in the development of the composition.[1]

The paint was applied using small brushes and fluid, brushmarked strokes, generally wet-into-wet and in opaque tones, for the basic color and forms of both architecture and figures. Precise architectural details were painted over the general forms of the building, probably with the use of a straightedge and compass. The figures are more broadly painted than the architecture, with details, shadows, and highlights quickly sketched over the opaque basic tone that gives them general form and modeling. Often the brush was held so that one side was more heavily loaded than the other, creating strokes and highlights in one application. The rich, varied textures of marble and stone were suggested by stippling and by dragging the dry brush through wet paint.

Although most of the tacking margins have been removed, remnants of the unpainted fabric are present and the painted image appears to retain its original dimensions. The black costumes are abraded and there are minor losses at the edges of the painting. The painting was relined by Stephen Pichetto about 1930. Removal of overpaint and discolored varnish during treatment by Ann Hoenigswald in 1992 has revealed the original design of the composition, an arched top within the rectangular canvas. The unpainted spandrels were painted out to the edges after 1925,[2] possibly in 1930. Scientific analysis identified modern pigments in these areas.

[1] X-radiographs confirm Panini's practice of changing his preliminary design by the addition of figures and adjustments to the trabeation. See also Cleaveland Museum of Art 1982, 383, for a discussion, based on x-radiographs of the museum's 1747 version of the subject, of similar compositional changes made after the initial layout was established. [2] The 1925 sale catalogue (see provenance) refers to the painting as having an arched top.


THE PANTHEON

Illustration by David A. CollinsBuilt: 120-126 AD under Emperor Hadrian
Foundation: 24’ thick at base and steps to 21’ at ground level
Rotunda: concrete, 20’ thick 142’ diameter
Oculus: concrete: 7.5’ thick 27’ diameter
Interior Columns: 3’ diameter, 29’ tall topped with a corinthian capital
of 4’ totaling 32’ 9" tall, 25 tons each
Portico: 16 granite columns 39’ tall, 5’ diameter, 60 tons each

The Monolithic Dome and The Pantheon

Monolithic’s President David South says that in building Monolithic Domes we have three major advantages the Pantheon’s builders simply did not have:

  1. Airforming – The Romans created the Pantheon’s form with earthworks and timber – an arduous, time-consuming process. We can inflate a giant Airform in less than two hours. The Airform has the additional advantages of being portable and ultimately becoming the roof membrane of the finished structure.
  2. Concrete – The Pantheon’s concrete was a mixture of pozzolan, lime and a small amount of water. That mixture was tamped – not poured – into place. Today, we have portland cement, which is easily ten times stronger and much easier to work with.
  3. Rebar – All concrete is weak in tension. We strengthen our concrete with reinforcing steel (rebar). The Romans did not have that option. They used ropes of vitreous china for reinforcement. To further compensate for the weakness and weight of the concrete, the Romans built extremely thick footing and drum walls. Otherwise, the weight of the dome would have spread the vertical walls of the drum and the Pantheon would not have lasted.

Note: Reprinted from our Summer 2001 Roundup.

Pantheon – 17th Century — This drawing by Giovanni Battista Falda dates back to the late 17th century. The Pantheon was defined as a temple to all gods. Pope Urban VIII (1623-1644) added the two bell towers designed by Bernini. They were removed in 1833.

Visitors from all over the world visit the Pantheon, one of the oldest intact buildings of antiquity. (Jan Kraus)

Map — A 1625 map by Giovanni Maggi shows the Pantheon within its environment.

A lasting attraction — Every day hundreds of visitors enter the Pantheon through its grand doors and into its exquisite symmetry. (Kalervo Koskimies)

Memorial niches — Along the interior walls, marble columns frame niches with memorial portrait busts. (Kalervo Koskimies)

Elaborate crowns — Corinthian capitals crown the columns in the alcoves. (Kalervo Koskimies)

High altar — Using the design of Alessandro Specchi, Pope Clement XI (1700-1721) rebuilt the high altar and apse in the sanctuary. (Kalervo Koskimies)

Chapels — The Pantheon, dedicated as a Catholic church and renamed Santa Maria ad Martyres (Our Lady and the Martyrs) has several small chapels, each decorated with priceless artwork. (Kalervo Koskimies)

Admired through the ages — No one knows the Pantheon’s exact age, but people – including notables such as Michelangelo – have admired it for centuries.


Analysis of the Major Sections of the Pantheon

Construction (Foundation)

The Pantheon was built on a location that was naturally marshy, unstable blue clay earth. This clay cycled through wet and dry four times a year due to the Tiber River flooding or changes in water level. This posed the potential to have a very problematic foundation because with such an unstable base, portions of the structure can settle or sink (Moore 1995). It is tolerable if the entire structure settles at a uniform rate and to a uniform depth, but if different parts of the foundation settle at different rates and depths, then the foundation could undergo stresses that it was not designed for. If this were to occur, the walls of the Pantheon would be put under a large amount of bending stress, and this could cause the concrete to crack and fail in shear.

With such a massive structure as the Pantheon, it was important to make sure the foundation was capable of supporting all the weight of the concrete, bricks, and marble above it. The original design for the foundation of the Pantheon consisted of a concrete ring that was 7.2 meters wide, only about 1.2 meters wider than the walls it would support, and 4.7 meters deep into the ground from floor level. However, during a point in the final phases of construction, the foundation cracked, so a second ring was then added in order to hold the first the ring together. The second ring was 3 meters wide and resulted in a final concrete ring foundation of about 10.2 meters (Moore, 1995).

Materials (Foundation)

The concrete used to make the foundation is pozzolan concrete, which consists of travertine aggregate in layers, held together by a mortar of lime and pozzolan (Moore, 1995). Roman concrete was made out of three components: pasty hydrated lime, pozzolan and pieces of aggregate. Most often these materials were found in abundance and shipped from relatively nearby to Rome The lime was made from limestone, consisting of mostly calcium carbonate, that was heated in a kiln to undergo a chemical reaction and release the gas in the limestone. After burning for days, the product in the kiln was a soft quicklime that, when mixed with water, becomes pasty and hardens as it dries. The second ingredient of concrete, pozzolan, is a volcanic ash that is composed of an amorphous silica compound. When mixed with the liquid lime slurry, the large holes in the molecular structure of the pozzolan are filled and expand to lock other pieces together. The last ingredient, rock aggregate is added or the concrete is laid directly onto a layer of aggregate for further mass and strength. The processes involved in creating and using concrete require a lot of chemistry when creating a usable form of lime, when mixing the different amounts of the ingredients, and then letting the concrete dry for the correct time, at the right thickness for the structure to form and harden correctly. The Romans used a system of ratios to determine how to mix the best concrete using certain material
(Moore, 1995). It is fairly humbling considering that the Romans knew nothing of molecular chemistry, their concrete was made through trial and error, yet they were able to come up with concrete comparable to modern concrete, that is in terms of the types of materials used to make it, but not necessarily comparable to modern concrete’s far superior strength.

To construct the foundation they first dug circular trenches and lined them with wooden boards to create the mold for the concrete. They then compacted the concrete over layers of rock pieces and allowed to dry (Parker, 2009). Compaction was a very important step, and Vitruvius showed how detailed it must be when he wrote that “when stamping is finished it must be…three quarters of its initial height” (Moore, 1995). The compaction was important to making the concrete strong and durable because a chemical reaction must take place and the compaction of the concrete pushes the molecules closer together by removing any air gaps and extra water. When in closer proximity and without extra water in the way, the atoms of pozzolan and of lime can better bond by sharing electrons and this created a durable concrete (Moore, 1995).

Structural Behavior (Foundation)

This original design, where the foundation was only about 1.2 meters wider than the 31.7 meter tall walls it would support, which makes Moore suggest that the Romans may not have fully understood how much sinking could occur and how much of a foundation would be needed. The walls at Pompeii are another example of the Romans sparing use of foundational support, because there is no discernible foundation for the 8 meter high and 5.5 meter thick wall. With the foundation of a structure being arguably the most vital element for longevity and stability, considering that the planned foundation of the Pantheon seemed to be somewhat meager and built on top of wet clay, it is amazing that the structure has stood to be as stable as long it has. Of course, they did add more foundation after the first ring cracked, but it is uncertain what has prevented the destruction of the structure, whether it be the lack of stress concentrations points on the foundation, very strong concrete, and/or something else (Moore 1995).


The Shape and Layout of the Coffers

The research is conducted in two phases. It begins with a study of the general layout of the coffers relative to the sphere, together with horizontal and vertical orientations of the 28 sectors and 5 levels. Subsequently, a closer analysis of the shape and geometry of the coffers is proposed, providing a set of metric data that have been processed on the basis of the results from the previous survey and proposing design criteria for the construction of the ideal sector of the coffers. The following factors have been considered.

Division of the circumference into 28 equal parts

Location of the axes of the bisectors of the sectors

Average circumferences passing through the vertex of the coffers: concentricity and orientation

Vertical external lines of the convergence of the coffers.

Analysis of surface geometry

Dimensions study: calculation of averages and study of diminution of dimensions

Vertical stripes between sectors and horizontal stripes between levels

Convergence of transition surface directions

Comparative study of the perspective projection of the coffers

Proportion of external and inner shapes of coffer levels.

General Arrangement

The division of the hemisphere into 28 equal parts was difficult to obtain at the time of construction. The division of a quarter of the circumference into 7 equal parts was a complicated geometric problem (Martines 1989). Moreover, the setting out on site was especially difficult at the location of the cornice of the vault. The choice of this complex division may be associated with cultural and symbolic reasons (Lucchini 1996: 109 Wilson Jones 2000: 183) or with the special proportions of the coffers adapting to the spherical surface (Saalman 1988: 121).

Pelletti (1989: 17) described the ancient method of dividing a circumference using strings, but stated that it would not have been possible to use this method for the Pantheon’s dome due to the scope of the project and the presence of scaffolding structures. Taylor (2006: 199) proposed the hypothesis that the division was made on the floor and then disassembled and reassembled at the site of the cornice line. This system allowed for a reduction of possible mistakes, but it would also stop construction for a considerable period of time. Waddell (2008: 84) put forward a theory about the mathematical division of the circumference into 28 equal parts by using a specific number of Roman feet.

According to the calculations of the present study, the accuracy of the radial distribution of the coffers is surprising (Fig. 5). When observing deviations in the plan between the bisectors of the coffer sectors and the axes that theoretically divide the circumference into 28 equal parts, the average recorded deviation barely reaches 0° 36′ (Table 1). The angles between vertical axes of the coffer sectors are extremely close to 12° 50′, which is equivalent to the subdivision of the 360° ideal model into 28 equal parts.

General arrangement: analysis of the accuracy of the main axes and of the distribution of bisectors of the sectors

We noted that the axis of the coffer sector situated opposite the entry portal is parallel to the North–South axis at a distance of 15 cm. This detail may indicate that the division of the circumference into 28 equal parts might have been started or completed with this sector.

If we observe the alignment between the sectors of quadrants I and III, we can see that the six opposing coffer sectors are perfectly aligned. However, the sectors of quadrants II and IV are not aligned with their opposites. The maximum divergence is registered in the two sectors of quadrants II and IV, where the bisectors reach a distance of 39 cm from the centre of the ideal sphere.

We continued the observation of the general arrangement by studying the main axes in plan view.

The accuracy of the orientation of the North–South axis stands out for its precision if we compare it with other Roman buildings with similar dimensions. For example, the Coliseum shows a more pronounced gap in the orthogonal direction of the main axis (Pelletti 1989: 15). In studying the division of the circumference into four quadrants, it is evident that the longitudinal and transversal axes are approximately orthogonal. However, we can also observe that the four lines that result slightly diverge from the centre of the ideal sphere. The East transversal axis shows a distance from the centre of the sphere of approximately 16 cm and the West transversal axis has a slightly greater value. The two parts show a minimum deviation from the perfect orthogonality: 90° 50′ between the East transversal axis and the longitudinal axis 90° 32′ between the West transversal axis and the longitudinal axis.

Another topic included in this research is the verification of the horizontality of the different coffer levels. The average circumferences following the points defined by horizontal edges generally present a slight slope relative to the horizontal plane, with an average value of approximately 0° 19′ (Fig. 6). All maximum slope lines of the planes defined by the circumferences are oriented northwest/southeast.

Average circumferences passing through the external points of the coffers: analysis of horizontality and concentricity

The upper circumference of the last level of the coffers shows a greater inclination than the average value, and it is directed towards the North direction. This difference may evidence an actual defect in the design construction if compared with the other levels, even if the value is very slight (0° 27′ with the horizontal plane). The average circumferences are approximately concentric. The main distance between the centre of the circumferences and the centre of the ideal sphere is only 7 cm. These data provide new affirmation of the incredible accuracy of the vault to the ideal model, and also confirms the uniformity of the general distribution of the coffers.

By studying the shape of the vertical sectors, it can be seen that the curves representing the alignments of the external points of the coffers do not converge towards the sphere’s pole, as might be assumed (Fig. 7). Based on our study of the bisectors of the coffers, the sectors tend to converge with high approximation towards the centre of the sphere. The external limits of the coffers might have been traced from them according to a system based on the accuracy of the bisector design.

Alignments of the external edges of the coffers showing that they do not converge in the upper pole of the sphere

The extension of these external lines of each sector generates a vertex at a certain distance from the centre of the sphere. The locations of these points do not approximate a circumference but rather show evident irregularities. If we attempt to establish a relation between this fact and the analysis of the dome surface, it appears that the arrangement of the vertexes somehow reflects the presence of deformed areas in the North–South zone of the dome. In fact, the vertexes that present the greatest distance from the centre are located in this area.

Shape and Geometry

The continuous reduction of the dimensions and variations in coffer shape, when adapted to the curvature of the sphere, result in a harmonious design of the dome soffit. The visual perception of the coffers is influenced by the inner surface proportions and the diverse directions of the transition surfaces.

The Romans used coffers in barrel vaults, but there are few surviving examples of double-curvature surfaces. One of the most ancient examples is the vault of the sanctuary of Fortuna Primigenia, which dates from the end of the second century B.C. (Lugli 1957: Tav. CCIX). In this case, the coffers have a trapezoidal shape and allow a complete perspective vision adapting to the vault surface.

In the Thermal Baths of Trajan and in the Pantheon, we find the first preserved examples of coffers adapted to a spherical surface (Waddell 2008: 58). Fine Licht (1968: 276) and Wilson Jones (2000: 192) noted the relevance of the perspective design and radial distribution of the coffers of the East room of the Baths, while the remaining structures cannot be evaluated due to their poor state of conservation.

In the Pantheon the coffers that appear square to the eye actually have a trapezoidal shape. The control of visual effects may be directed to establish a connection between coffer distribution and the pavement grid, which is composed of large squares. The dimensions of the floor squares are visually similar to the image of the dome coffers (Waddell 2008: 85) (Fig. 8).

Arrangement of coffers. Study of the alignment through calculated average of the positions of the survey points

Many authors, including Fine Licht (1968: 140) and Waddell (2008: 85), have stated that the coffers of the Pantheon’s dome do not play a constructive or structural role but are merely decorative elements. Their function is primarily related to visual perception, which may justify their complex design.

We began the analysis by studying whether the different surfaces making up the coffers are spherical or flat (Fig. 9). An ideal flat surface was created with successive calculations on each of the intermediate and deepest levels of one sector of coffers. The distances of the raised point from this flat average surface were minimal (2–3 cm). It can thus be deduced that the intermediate and the deepest levels do not adapt to a spherical surface but tend to be flat, which would undoubtedly make it easier to control the formwork.

Photograph of the internal surfaces of the coffers

One of the dome quadrants was carefully studied: dimensions of six sectors of coffers were recorded, and the data were processed through a calculation of averages to obtain reference values of their measurements. We drew an orthogonal projection of each coffer of the second sector of the North-East quadrant. Even if these projections are orthogonal, they reduce the actual length of the curves due to their restitution onto a plane. Moreover, we proposed another calculation of the length of the arcs that defines the external edges of the coffers. The values of sectors 2, 3, 4, 5 and 6 of the North-East quadrant were registered and used to obtain the average values (Table 2).

The results show a gradual decrease of the length of the vertical arcs of the coffers. The average values from the first level (A) to the last level generated a numerical progression:

This progression increased with the upper levels and was related to the different perception of the curvature of the vault. The last level of coffers shows the greatest difference with the previous level.

The width of the coffers also progressively decreased as they progressed towards the upper levels. The difference between the upper and lower edges of each coffer increased in the higher levels, reflecting the necessity to adapt to the spherical curvature. The upper width of the last coffer was approximately half of the lower length of the coffers at the first level. The analysis shows that the coffer sector of the North–South axis opposite from the entrance portal has a major difference in width (the coffer of the first level of this sector, named A1, measures 4.00 m in its lower part, whereas the rest of coffers measure as follows: A2, 3.90 m A3, 3.94 m A4, 3.86 m A5, 3.83 m A6, 3.86 m A7, 3.85 m A8, 3.92 m). This difference has an impact on the radial arrangement of the coffers and generates the divergence of the bisector that was registered by the comparison of the survey model and the ideal model. Moreover, as in our previous study (Aliberti et al. 2014), the bisector of this sector shows a gap with the North–South axis. This divergence from the average value was distributed evenly between the six sectors of the second quadrant in order to generate a uniform image of the soffit frame.

The results suggest that the division of the circumference into 28 equal parts could not be controlled by rigid geometrical construction the layout of the coffers was adapted to the slight divergences of the North–South sector to determine a uniform distribution using an empirical method. The setting-out on site may have been performed through a practical-constructive technique based on experimentation more than complex geometrical laws.

The depth of the intermediate surfaces changed at different coffer levels. Using the section passing through the vertical axis of the coffer sector, we studied the second sector of the North-East quadrant (Fig. 10). As we can see in Table 3, there is a small and gradual decrease in depth from the first level to the fifth level. The slight divergence recorded between the first three internal surfaces measures a maximum of 4 cm. It is evident that the greatest decrease in depth appears in the last surface. This fourth surface disappears in the upper level of the coffers therefore, the third surface follows a different design.

Coffer dimensions. Vertical section and orthogonal projection of the coffers of sector 2 of the North-East quadrant

Unlike the coffer width and height variations, the horizontal bands separating the coffers have very similar dimensions. When calculating these values as arcs of a sphere, the average value is 0.84, with variations of a few centimetres between zones. This regularity is also reflected in the separation between the vertical sectors of the coffers. Based on the study of the North-East quadrant, the average distance between the lowest external points of the first level is 1.02 m, which becomes 0.67 between the upper external points of the last level. According to these data, the meridian rib is reduced to almost half of its width from beginning to end, a fact that is not perceived from the overall view of the dome, where these strips appear to have almost uniform dimensions. We used these studies on the average measurement of coffers and their distribution as a first metrical reference to build the complete ideal model.

In analysing the direction of the transition surfaces between the different levels, the radial tracings were identified, and other tracings approximately converged into certain reference points outside the coffers (Fig. 11).

Study of the direction of the transition surfaces: average calculation applied to the rotation of the radial sections and hypothesis of ideal alignment

These connecting planes are much shorter than the dimensions of the entire dome therefore, it is difficult to provide an exact definition of their directions. Nevertheless, we can note that the upper connecting surfaces appear to be orthogonal to the spherical surface of the dome. The inferior transition surfaces present a greater inclination in order to open the visual field and leave every edge of the coffers visible.

We interpreted these convergences in the construction of the ideal model (Fig. 12). Here, the upper connecting surfaces were built as radial, and the inferior ones converged to a point at a certain distance from the centre. Although the constructed object is not as exact as the ideal model, these convergences indicate that there is a circular zone where a viewer can see all the inferior edges of the coffers and almost all the upper edges.

View of the complete ideal model as result of the geometrical analysis

In studying this subject, we should consider that the results are based on the current state of the coffers registered by the point cloud. They may have been slightly modified by the cladding restoration works of Terenzio (1933) in the 1930s and more recently of Belardi (2006), especially if we refer to the smallest surfaces.

The coffer arrangement allows complete visibility from the centre of the floor. This observation has been verified through the study of the point cloud generated from the centre of the room without considering scannings performed on the transversal and longitudinal axes. This unique point cloud perfectly describes every part of the coffers and their complex surfaces without detecting any blind areas. The present research, performed with sophisticated devices and software, verifies the ambitious work of the Roman builders based on empirical knowledge of perception and geometry and carried out with the use of ancient tools.

To perform specific studies of the coffer design, a set of alignments was drawn employing tools that apply average calculations. The drawing of the diagonal lines connecting the external vertices of each coffer’s transition surface was uniformly repeated in all of the sectors (Fig. 13). There was a progressive variation in the inclination of the diagonals, which in the first levels clearly pointed towards the upper part of the coffers and gradually declined in the last levels.

Elevation of each coffer sector of the North-East quadrant. Study of alignment and proportions

To appreciate the perspective attributes of the coffers, a series of projections was performed from different points of view. By comparing different perspective views, it can be directly noted how the perception of these elements slowly changes.

We began the study by generating a frontal perspective view of each coffer of the second sector of the North-East quadrant. The point of view was located in the centre of the room and at a man’s height of 1.70 m. It is evident that this perspective view reproduces an almost square image, and the coffer surfaces seem to be regular and of the same dimensions. The perceptive differences of the coffer parts are not visible from the centre of the room.

Each coffer generates a different image when the inclination of the perspective axis moves, thus showing its trapezoidal shape. Creating the image of a pure shape, such as a square, is part of the search for regular forms present in the classical Roman culture (Fernández-Cabo 2013: 543). This image of a square may be associated with the external shape of the coffers, while the inner levels show some differences (Fig. 14).

Study of the proportions of the inner levels applied on the survey model orthogonal views and perspective projection from the centre of the room of the coffers of the North-East quadrant

If we approximate the form of the inner levels of the coffers to rectangles, it is evident that their proportions change from the horizontal to the vertical. This change is probably a result of two conditions of coffer design: the aim to preserve the vertical alignment of the sector in the width of both the external and internal levels and the need for greater alteration of the lowest coffers to control the perspective view from the centre of the room. The lowest connecting planes in the first two levels of the coffers are larger than in the upper levels and the inner figure is thus a horizontal rectangle. From the third level to the fifth, the inner figure is a vertical rectangle. Moreover, the differences between the second and the third level are greater than between the rest of the levels, so the transition seems not to be completely uniform. In any case, it is highly relevant that these rectangles with different proportions are approximately centred in a perspective view from the centre of the room.

Based on these studies, we can state that the design of the inner levels of the coffers seems not to depend on the projection from a hypothetical point, in contrast with some scientific studies. We consider that from the point of view of construction, such a dependence would be very difficult to achieve due to the great distance and the height of the dome from the floor. Furthermore, as far as we currently know, in ancient times there was no knowledge of the perspective method or of spherical geometry.


Contents

Site and earlier buildings Edit

The site of the Panthéon had great significance in Paris history, and was occupied by a series of monuments. It was on Mount Lucotitius, a height on the Left Bank where the forum of the Roman town of Lutetia was located. It was also the original burial site of Saint Genevieve, who had led the resistance to the Huns when they threatened Paris in 451. In 508, Clovis, King of the Franks, constructed a church there, where he and his wife were later buried in 511 and 545. The church, originally dedicated to Saints Peter and Paul, was rededicated to Saint Genevieve, who became the patron saint of Paris. It was at the centre of the Abbey of Saint Genevieve, a centre of religious scholarship in the Middle Ages. Her relics were kept in the church, and were brought out for solemn processions when dangers threatened the city. [4]

Construction Edit

Soufflot's original plan for the Church of Saint Genevieve (1756)

Soufflot's final plan: the principal facade (1777)

Soufflot's plan of the three domes, one within another

Looking upward at the first and second domes

Iron rods were used to give greater strength and stability to the stone structure (1758–90)

King Louis XV vowed in 1744 that if he recovered from his illness he would replace the dilapidated church of the Abbey of St Genevieve with a grander building worthy of the patron saint of Paris. He did recover, but ten years passed before the reconstruction and enlargement of the church was begun. In 1755 The Director of the King's public works, Abel-François Poisson, marquis de Marigny, chose Jacques-Germain Soufflot to design the church. Soufflot (1713–1780) had studied classical architecture in Rome over 1731–38. Most of his early work was done in Lyon. Saint Genevieve became his life's work it was not finished until after his death. [5]

His first design was completed in 1755, and was clearly influenced by the work of Bramante he had studied in Italy. It took form of a Greek cross, with four naves of equal length, and monumental dome over the crossing in the centre, and a classical portico with Corinthian columns and a peristyle with a triangular pediment on the main facade. [6] The design was modified five times over the following years, with the addition of a narthex, a choir, and two towers. The design was not finalised until 1777. [7]

The foundations were laid in 1758, but due to economic problems work proceeded slowly. In 1780, Soufflot died and was replaced by his student Jean-Baptiste Rondelet. The re-modelled Abbey of St. Genevieve was finally completed in 1790, shortly after the beginning of the French Revolution.

The building is 110 metres long by 84 metres wide, and 83 metres high, with the crypt beneath of the same size. The ceiling was supported by isolated columns, which supported an array of barrel vaults and transverse arches. The massive dome was supported by pendentives rested upon four massive pillars. Critics of the plan contended that the pillars could not support such a large dome. Soufflot strengthened the stone structure with a system of iron rods, a predecessor of modern reinforced buildings. The bars had deteriorated by the 21st century, and a major restoration project to replace them is being carried out between 2010 and 2020. [8]

The dome is actually three domes, fitting within each other. The first, lowest dome, has a coffered ceiling with rosettes, and is open in the centre. Looking through this dome, the second dome is visible, decorated with the fresco The Apotheosis of Saint Genevieve by Antoine Gros. The outermost dome, visible from the outside, is built of stone bound together with iron cramps and covered with lead sheathing, rather than of carpentry construction, as was the common French practice of the period. Concealed buttresses inside the walls give additional support to the dome. [9]

The Revolution – The "Temple of the Nation" Edit

The Panthéon in 1795. The facade windows were bricked up to make the interior darker and more solemn.

The Church of Saint Genevieve was nearly complete, with only the interior decoration unfinished, when the French Revolution began in 1789. In 1790, the Marquis de Vilette proposed that it be made a temple devoted to liberty, on the model of the Pantheon in Rome. "Let us install statues of our great men and lay their ashes to rest in its underground recesses." [10] The idea was formally adopted in April, 1791, after the death of the prominent revolutionary figure, The Comte de Mirabeau, the President of the National Constituent Assembly on April 2, 1791. On April 4, 1791, the Assembly decreed "that this religious church become a temple of the nation, that the tomb of a great man become the altar of liberty." They also approved a new text over the entrance: "A grateful nation honors its great men." On the same day the declaration was approved, the funeral of Mirabeau was held in the church. [10]

The ashes of Voltaire were placed in the Panthéon in a lavish ceremony on 21 July 1791, followed by the remains of several martyred revolutionaries, including Jean-Paul Marat, and of the philosopher Jean-Jacques Rousseau. In the rapid shifts of power of the Revolutionary period, two of the first men honored in Pantheon, Mirabeau and Marat, were declared enemies of the Revolution, and their remains were removed. Finally, the new government of the French Convention decreed in February, 1795 that no one should be placed in the Pantheon who had not been dead at least ten years. [11]

Soon after the church was transformed into a mausoleum, the Assembly approved architectural changes to make the interior darker and more solemn. The architect Quatremère de Quincy bricked up the lower windows and frosted the glass of the upper windows to reduce the light, and removed most of the ornament from the exterior. The architectural lanterns and bells were removed the facade. All of the religious friezes and statues were destroyed in 1791 it was replaced by statuary and murals on patriotic themes. [11]

Temple to church and back to temple (1806–1830) Edit

Napoleon Bonaparte, when he became First Consul in 1801, signed a Concordat with the Pope, agreeing to restore former church properties, including the Panthéon. The Panthéon was under the jurisdiction of the canons of the Cathedral of Notre Dame de Paris. Celebrations of important events, such as the victory of Napoleon at the Battle of Austerlitz, were held there. However, the crypt of the church kept its official function as the resting place for illustrious Frenchmen. A new entrance directly to the crypt was created via the eastern porch (1809–1811). The artist Antoine-Jean Gros was commissioned to decorate the interior of the cupola. It combined the secular and religious aspects of the church it showed the Genevieve being conducted to heaven by angels, in the presence of great leaders of France, from Clovis I and Charlemagne to Napoleon and the Empress Josephine.

During the reign of Napoleon, the remains of forty-one illustrious Frenchmen were placed in the crypt. They were mostly military officers, senators and other high officials of the Empire, but also included the explorer Louis-Antoine de Bougainville and the painter Joseph-Marie Vien, the teacher of Napoleon's official painter, Jacques-Louis David. [12]

During the Bourbon Restoration which followed the fall of Napoleon, in 1816 Louis XVIII of France restored the entire Panthéon, including the crypt, to the Catholic Church. The church was also at last officially consecrated in the presence of the King, a ceremony which had been omitted during the Revolution. The sculpture on the pediment by Jean Guillaume Moitte, called The Fatherland crowning the heroic and civic virtues was replaced by a religious-themed work by David d'Angers. The reliquary of Saint Genevieve had been destroyed during the Revolution, but a few relics were found and restored to the church (They are now in the neighboring Church of Saint-Etienne-du-Mont). In 1822 François Gérard was commissioned to decorate the pendentives of the dome with new works representing Justice, Death, the Nation, and Fame. Jean-Antoine Gros was commissioned to redo his fresco on the inner dome, replacing Napoleon with Louis XVIII, as well as figures of Louis XVI and Marie Antoinette. The new version of the cupola was inaugurated in 1824 by Charles X. As to the crypt where the tombs were located, it was locked and closed to visitors. [13]

Under Louis Philippe I, the Second Republic and Napoleon III (1830–1871) Edit

The French Revolution of 1830 placed Louis Philippe I on the throne. He expressed sympathy for Revolutionary values, and on 26 August 1830, the church once again became the Pantheon. However, the crypt remained closed to the public, and no new remains were added. The only change made was to the main pediment, which had been remade with a radiant cross it was remade again by D'Angers with a patriotic work called The Nation Distributing Crowns Handed to Her by Liberty, to Great Men, Civil and Military, While History Inscribes Their Names.

Louis Philippe was overthrown in 1848 and replaced by the elected government of the Second French Republic, which valued revolutionary themes. The new government designated the Pantheon "The Temple of Humanity", and proposed to decorate it with sixty new murals honouring human progress in all fields. In 1851 the Foucault Pendulum of astronomer Léon Foucault was hung beneath the dome to illustrate the rotation of the earth. However, on complaints from the Church, it was removed in December of the same year.

Louis Napoléon, nephew of the Emperor, was elected President of France in December 1848, and in 1852 staged a coup-d'état and made himself Emperor. Once again the Pantheon was returned to the church, with the title of "National Basilica". The remaining relics of Saint Genevieve were restored to the church, and two groups of sculpture commemorating events in the life of the Saint were added. The crypt remained closed.

The Third Republic (1871–1939) Edit

Saint Genevieve bringing supplies to Paris by Puvis de Chavannes (1874)


The Pantheon and Piazza Navona - history and romance combined - a must-do on any Rome sightseeing tour.  And of course you just cannot leave Rome without seeing the famous Trevi Fountain!

We have partnered with one of the most trusted of all tour companies in Italy, Viator Tours, to provide you with an amazing guided walk seeing all three.  Learn their history, experience their magic - it's a breathtaking combination.

Just click on the picture above to go to Viator's page where you can see how satisfied other people have been before you book. 


Pantheon Rome

Only in a city such as Rome could the Pantheon be considered quaint. Found in a city containing hundreds of opportunities to view overwhelming ruins, the Roman Pantheon slips dreamily into the landscape. Of all the great buildings constructed during the crest of the Roman Empire, only this one still stands. Seemingly impervious to time or destruction, the walls and dome of the Roman Pantheon rise from Piazza della Rotonda, and bath the square in a warm, protecting light.

The history of Pantheon dates back to 27 B.C., when it was first conceived by Marcus Agrippa as a temple to the Gods (Pantheon meaning, of course, "all the gods"). Over 150 years later, emperor Hadrian oversaw its completion, and is credited with turning it into one of the most recognizable architectural works in the world. The cavernous space rises 142 feet into the air while its base measures the same - a perfect sphere astride a corresponding cylinder with an immense bronze ceiling. A hole at the dome's apex allows daylight into the majestic main room, a shifting spotlight that slowly fades into twilight and allows no defense against the rain or the occasional Roman snowfall. Pantheon history states that the interior of the roof is intended to symbolize the heavens, and the giant hole above is supposedly the eyes of the gods.

A precarious moment in the history of Pantheon was the fall of the Roman Empire. But unlike many institutions at the time, the Roman Pantheon managed to escape destruction as Barbarians flooded the city. Historians disagree as to why the conquerors elected to preserve this building while destroying so many others, and thus their motives may forever remain a mystery. Regardless, it was the pivotal moment in Pantheon history.

Rome Map

Beneath the light and between the granite Corinthian columns, seven sculptures stand. These Roman gods correspond to each of the seven planets (at the time) and remain in their original spots, despite the church being consecrated as a Christian church by Pope Boniface IV in 609. But the Roman Pantheon seems to exist independent of religious rule - more a tribute to the past than any specific spiritual figures. The history of Pantheon was forever changed during the reign of Pope Urban VIII, who melted down every scrap of bronze located upon the ceiling, outraging a great deal of Roman citizens. The great bronze doors escaped destruction, however, and remain today, a glowing testament to Pantheon history.

As the best preserved example of monumental Roman architecture, the Pantheon was enormously influential on European and American architects from the Renaissance to the 19th century. Michelangelo studied the dome before creating the cupola of St. Peter's. The concrete used to create the famous dome is one of the great examples of the progressiveness of Roman culture in the first millennium. In fact, the exact composition of the material is still not known, but appears to be structurally similar to modern day concrete. Well ahead of its time in almost every aspect, the Pantheon is a definite must-see in a city full of them.


Art History

SUMMARY: The Domes of Heaven are magnificent. I could leave it at that however there is more that can be said. It is impressive the time, effort, and skill that was put into constructing each of the domes. They can't be considered just a dome overhead they are a work of art, a creation, a gift to those that are fortunate enough to enjoy them. They are all massive works of art.

REASON: The reason behind this question is to see the differences between techniques used to construct the domes. What might have been a factor in why and how they were built. To see the beauty in architecture.

PURPOSE: I chose this question because I found it interesting. The images caught my attention. I have always had an interest in architecture.

IMPRESSIONS: The domes are very impressive and awe inspiring. I want to go visit the three mentioned and others that I found in my search. I would love to go and measure the Pantheon and see what the exact dimensions are.

Each dome is unique in its own way. They have a different style and have used different materials. The type of construction is different between the different domes. They do have similarities. Each one is recognized for their own distinct features. Although they may have a similar theme, they are all fascinating in their own way.

The Pantheon is one of the simplest and most impressive domes. "The Pantheon is a circular temple, 142 feet 6 inches in diameter. It's internal height is exactly the same, and the dome is semi-circular. In other words, a sphere 142 feet 6 inches in diameter would fit exactly inside the Pantheon . It was dedicated to the deities of the seven planets. Its spherical form is symbolic of the cosmos. The great 'eye' in the dome, 27 feet across, is the only source of light, and was symbolic of the sun the bronze stars originally set in each coffer were the stars of heaven. Externally the dome was once covered with golden tiles so that seen from the surrounding hills it again symbolized the sun" ( A Concise History of Western Architecture, R. Furneaux Jordan, 1983 Thames and Hudson Limited London, pages 56, 57 )

I have found there is a discrepancy on the size of the dome. The huge bowl shaped dome is 143 feet in diameter and 143 feet from the floor to the summit and the oculus is 29 feet wide in diameter. ( Art History, Marilyn Stokstad/Michael W. Cothren, Fourth Edition/volumn 1, 2011 Pearson Education, Inc., page 197 ) One text tells us the sphere is 142 feet and 6 inches with the 'eye' diameter of 27 feet. The other text tells us the sphere is 143 feet with the oculus diameter of 29 feet.

2 comments:

Helen - Nice job. It was a big question that required a big answer and you got as much in there as you could. I would have liked to see more in your closing because the one factor you didn't go deep into was technology ans with it discovery or the handing down of knowledge. The Romans created/developed building technology using concrete. That knowledge somehow never made it to the Renaissance. Even the knowledge that was present when the Hagia Sophia was built wasn't complete and even that didn't survive. These three building celebrate and were used to celebrate three religions and yet one religion (Christianity) thwarted the transfer of this technological knowledge. All in all, not bad and you followed the format and so on a scale of 1 to 4, this was a 3.7


Stay near the Pantheon

The area around the Pantheon is one of the best areas to stay in Rome, especially for first time visitors. You cannot beat the atmosphere and aura of this ancient structure but it is also within walking distance of Rome’s major attractions. The Colosseum, Vatican, Trevi fountain and Piazza Navona are all within 20 minutes’ walk of the Pantheon.

A short stroll down the cobbled streets takes you to vibrant Campo de’Fiori. This bustling market square is also home to great restaurants and bars.

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Watch the video: Climbing the Pantheons Dome on Pentecost - EWTN Vaticano (May 2022).