To say with any precision what the Pantheon meant to Hadrian and his contemporaries will probably never be possible. The words of William MacDonald, a regarded scholar of the Pantheon of our time, suggest the mystery with which this awesome and inspiring structure has traditionally been viewed. Scholars have concentrated their efforts on studying archaeological ov*dcnce and written sources which havo, in combination, provided considerable illumination respecting the structural and historical characteristics of this most impor tant surviving work of Roman architecture. Yet its moaning is still described as ‘enigmatic” and ‘problematic.’
From 1923 when Arturo Graf suggested the Pantheon was dedicated pri marily to Saturn; to 1968 when Kjeld OeFine Licht thought it might be a monument to the gens Julia and its divine ances tors; to 1984. when Henn Stiertin viewed it as a solar temple, to 1989 when Gtangiacomo Martinos arguod that its cupola is a unique example of ideal geometry, no consensus has been achieved-2 Recently MacDonald indicated that the meaning of this extraordinary and unique structure lies—beyond its dedi cation to all the gods in its rote as the temple of Rome and a* things Roman, the Empire, and the whole world While ail these suggestions havo boon usotul to this study, this paper will attempt to pursue a different avenue of inquiry that will suggest that the Pantheona building about whose meaning even its earliest known desenber. a century after its construction.
Was uncertain was designed by Hadrian for a very specific purpose His purpose in erecting In tho center of the city of Rome in an area dedicated to the cult ot the omporor not just another temple, but tho most grand, mnova tive, difficult, and complex secular temple of Roman antiquity, must have been intended to convoy to the Roman intelli gentsia it not to the Roman people a very carefully crafted and distinct meaning. In order to discover this meaning it will be necessary to review what Is now generally agreed, in order to underline that the building in its entirety was built by Hadrian and to show that it survives essentially Intact as his structure. Subsequently In reading the structure as a Pylhagorean com position that is orderly, beautiful and symbolic, it will be sug gested that a Pythagorean scheme of numbers as known and admirod in Hadrian’s time was used to create a sophisticated formulation that would have been better understood to con temporary observers than it can be to us today. Not only Hadrian s own Interests, but also peculiar events and circum stances m Ns life, will be brought together to suggest some reasons why Hadrian designed and such a stunning and novel structure.
It is hoped that introducing this new avenue of study will suggest some dues regarding the possible original meaning of the building and that these in turn may broaden the discussion of its particular architect, who has remained as elusive as Its meaning Ancient literary evidence offers little Information respect ing the original temple that formed part of a complex built by Marcus Vipsanius Aghppa In the Campus Martius. which con tained numerous other temples, attars and public buildings m the time of Augustus. Pliny the Elder, who saw Agrippa’s tem ple in the time of Vespasian’s rule, reters to It as Pantheum From his brief references, we know that this temple, complet ed in about 25 B.C.. was embellished with sculpture. Including caryatids, and figures on tho angles of the pediment in addi tion to a sculpture of Venus In the Interior.
Though Appian has much to tell us about Agnppa’s close friendship with 0 eta via n as well as his military and political activities, he. together with Suetonius, fails to provide information about the building of the original Pantheon. Writing after its destruction. Dio Cassius (who appoars to havo boon retying partly on tradition and partly on Ns knowledge of the Pantheon as rebuilt by Hadrian, a fact of which ho was unaware) tells us that a figure of Mars accompanied that of Venus and that a statue ot Julius Caesar had also been placed inside, while statues of Augustus and Agrippa were in the pronaos; because ot his use of tho past tense, there is little reason to believe that these statues survived in Hadrian’s building.6 Nonetheless it Is clear that from the time of its origin this temple had a civic as well as a religious function and that Its original purpose was linked to the gens Julio. Archaeological ovidenco toils us a great deal more.
We now know that Agnppa’s temple was a rectangular buiding whose facade, one of its two long sides, faced south The travertine foundations reveal that the structure was a decastyle temple, with ten columns on each long side.7 In front of the temple (to the south) opened a large round space enclosed by a non-supporting edge. The pavement of this space was not horizontal, its pavonazetto marble slabs sloped from the center downwards towards the circumference ot the cvcie.6 This slightly conical open circle, most kkely the site of its altar, was to become the site of the future rotunda Directly to the easi was the Saepta Julia, dedicated by Agnppa in 26 B.C., while to the west lay the Stagnum Agnppae and the Horti of Agnppa. To the south, beyond the large circular space, were the thermae of Agrippa. the first great Roman public baths.9 Excavations have also revealed traces ot an Intermediate pavement above Agnppa’s. that of Domitian who restored the Pantheon after its destruction m the great fire of 80 A.D.’° Some years later, in 110. the building was struck by lightning and agaxi burned down.” Seven years later the profligate and best ot emperor».’ Marcus Ulpius Traianus (Trajan), who ruled the Empire at the time, was to die on Ns way back to Italy from Syria, giving his successor.
Publius Aehus Hadrlanus (Hadrian), who was at the time governor of Syria, the opportu nity to rebuild on this sue.12 Hadrian’s ancient biographers are in agreement that at the time of Trajan’s sudden death in August of 117, Hadrian did not rush back to Rome. Rather he remained in Syria, accept ing tho imperial power which came to be his largely through the influence, if not manipulation, of Trajan’s wife. Plotina. from his post in Antioch.13 Hadrian appears to have remained in Syria until Juty of 118. when he finally returned to Rome to pla cate a Senate that regarded his choice as emperor with ambi guity and suspicion and to establish himself as the authorita tive power m the impenal city.’* Between this time and 120, when Hadrian travelled to Gaul, the Rhineland and Spain, fol lowed by an extended trip to Greece and the East until 127. is thus the likely moment in which plans for the new temple to be built on the site ot the former ones were drawn up and con struction begun It Is thus appropriate to assume the building was designed and begun xi 118-19. essentially constructed during the seven years Hadrian was absent from Rome (120- 27), and dcdicatod In about 127 when he returned.
As sug gested by the later testimony of Spartanue. archaeological evidence indicates this supposition Is true, based on the Iden tification of bricks used in various parts of the monument that bear stamps (botfe) of the time of Hadrian and are of the par ticular composition used in Rome between 115 and 127.,a Archaeological evidence has also discovered the name of Julia Sabina, the Empress of Hadrian, engraved on the columns of pavonazetto In the apse. These supported a bench on which Hadrian sat in the Pantheon to administer justice, as we are told by Dio Cassius17 The temple as rebuilt by Hadnan has been described and analyzed many times ’• it is not the purpose of this paper to add anything to the well established facts of its constructional and stylistic features. Most significantly, it was completely dif ferent from its predecessors on the site in that, approached by five marble sieps elevating the structure from the forecourt,’3 the octastyle porch, or pronaos. which supports an unusually high triangular pediment, leads to a barrel-vaulted entranco way.
A separate rectangular intermediate block as high as the entire building and as wide as the porch leads into the third geometric area, the primary space of the temple Defined by bnck and concreto structural elements and resting on a foun dation of concrete that contains targe travertine fragments, this spaco forms a large circular nng corresponding in diame ter and circumference with the formerly open paved space of Agrippa. Tho hoart of Hadrian’s structure is therefore clearly new in that it was not built on the foundation of any pre-exist ing building.
A great cylinder rises from the circular founda tion and this m turn supports the largest domed rotunda ever built, equal in height and radius to the cylinder below. The exterior of the dome was originally covered with guttering gold in the form of gilded bronze tiles.2′ while its interior, whose controlling geometry is based on a perfect central axis, is marked off by coffers that are aligned horizontally and verti cally over the sloping surface which culminates in an oculus of unprecedented dimension. Centrally located, over the interior space and poisod over the central circle in tho pavement below. the single source of light tor the entire building was ongmally crowned with an elaborate bronze, most likely also gilded, comice.
Among those who have suggested the pronaos is unrelat ed to the rotunda some have considered that, because its dimensions roughly correspond with those ot the foundation of the entire temple of Agnppa below, it might mcorporato remaining parts of Agrippa’s temple; others have debated whether it might have been constructed at a later date. The archaeological evidence is. again, steadfast showing that the entire structure as we know it, including the temple front porch, the intermediate block and the rotunda, were all built at once and by Hadrian.23 That the new temple had noth ng to do constructionally with the old Is underlined by the tact that its orientation was reversed, obviously for practical rea sons While Agnppa’s temple faced south. Hadnan’s facade is to the north, the only available space for a forecourt and altar.
The articulation ot the Interior space of the new temple makes It clear that the structure was oriented to the four cardinal directions. Not only was Hadnan’s the grandest temple ever built, also It was the most original in that it brought together, perhaps inspired by an idea that had earlier been demonstrat od in the Mausoleum ol Augustus. A podimentod porch and a circular construction, an event that in size, scale and grandeur was completely new tor a temple structure. There is nothing like it in Vitruvius’ description ot circular tem ple types, composed in the late first century B.C.25 From its exterior, the new temple incorporated the con ventional elomonts ot a monumental trabeated pedtmented temple front. Because the building was nestled between civic structures to east, west and south, the exterior view that Roman citizens enjoyed incorporated this traditional feature, crowned by a most unusual golden dome that could best be viewed from afar.
Reflecting the rays of the sun In a stunning focal point for the city, this visible image, crowned with gkstenlng golden and bronze sculptures and decorations, must have been a most impressive sight. Indeed, it formed a most unusual and sumptuous Interior space of equally extra ordinary dimension which must have Inspired astonishment and awe In its early visitors. Apart from all Hadrian’s other constructions, this was the one where he both worshipped and held courl as Emperor.26 Since the vicissitudes of fate have granted us neither descnpbon nor mention from the cen tury of its construction, we can only assume that it continued to be known by its old name Panlheum in Hadnan’s time. Destiny was to prove relatively kind to the Pantheon.