Eight The Pantheon in the Middle Ages

Erik Thunø

What happened to the Pantheon as a building during the passage of time between its Hadrianic dedication and its appropriation by the Church almost half a millennium later? The relevant facts are scarce, but there can be little doubt that the building was maintained as well as admired in the first centuries after its construction. Supporting this assumption is an inscription on the front architrave of the portico recording that the Rotunda was restored in AD 202.1 In the first half of the third century, the Christian historian Iulius Africanus (c. 160–c. 240) reports the establishment of a library in or near the Pantheon, which may suggest a change in the use of the building.2 In 357, the Pantheon was still in good enough condition to impress the emperor Constantius II during his visit to Rome from Constantinople. At the end of the fourth century, the Roman historian Ammianus Marcellinus (c. 330–c. 400) wrote that the emperor had been amazed at Rome’s buildings, including the Pantheon, which was “like a rounded city-district, vaulted over in lofty beauty.”3 By this time, Rome was changing into a Christian city in the wake of emperor Constantine the Great’s legitimization of Christianity in 313. At Constantine’s behest and with his sponsorship, the city received a cathedral, the Lateran Church, and the great basilica of St. Peter was rising over the body of the apostle outside the walls of the Eternal City, to be followed by an almost equally impressive basilica dedicated to St. Paul. Meanwhile, in 330, Constantine shifted the empire’s capital to Constantinople.4

It is uncertain how these significant urban, political, and religious events affected the Pantheon and the role it played in daily life in Rome. Its survival and reputation were such that, little more than a decade after Constantius’s visit to Rome, either in 368 or 370, the Rotunda was explicitly mentioned as the place in which an imperial law was announced to the public.5 Thereafter, we hear nothing about the Pantheon until the early seventh century, when Pope Boniface IV requested the emperor’s permission to transform the building into a church.

During the centuries preceding the conversion of the Pantheon, the material glory of ancient Rome was disintegrating. A significant number of urban spaces and buildings had fallen into a state of serious decay, and were gradually spoliated to furnish materials for the new Christian basilicas that were being built inside and outside the walls of the city. The situation was worsened during the fifth and sixth centuries when the city was besieged and sacked by foreign invaders on several occasions. The population shrank, and a number of heavy earthquakes and inundations from the Tiber certainly did their part to contribute to the city’s deterioration.6 We have no record referring specifically to the Pantheon and its status during these difficult times, but as one of the ancient city’s largest and most central monuments, it is hard to imagine that it remained unaffected. It was probably during this period, for instance, that the pagan statues reported to have adorned the interior of the ancient temple disappeared.7 How the building itself managed to survive can only be suggested by the account of the Byzantine historian Procopius (died 565): “[T]he Romans love their city above all the men we know, and they are eager to protect all their ancestral treasures and to preserve them, so that nothing of the ancient glory of Rome may be obliterated. For even though they were for a long time under Barbarian sway, they preserved the buildings of the city and most of its adornments, such as they could through the excellence of their workmanship notwithstanding so long a lapse of time and such neglect.”8

Whereas the Pantheon thus remained standing, much of what surrounded it in the formerly busy Campus Martius with its many public buildings must have quickly fallen into decay, since already in 398 there was a prohibition issued against the construction of hovels within or adjacent to the antiquities in the Campus Martius. Over the centuries, the gradual abandon and dilapidation of the ancient city also caused the ground level around the Pantheon to rise, giving the persistent impression that the Rotunda had sunk into the ground.9

The Christian Consecration

The long history of the Pantheon in the Middle Ages is inextricably bound up with the decision made during the pontificate of Boniface IV (608–615) to transform the ancient building into a Christian church.10 Because Rome was under Byzantine control during this period, the pope had asked the emperor Phocas (602–610) in Constantinople for permission to appropriate the building for the Church. The contemporary account of the life and donations of Pope Boniface (in the Liber Pontificalis) mentions briefly that “he [Boniface] asked the emperor Phocas for the temple called the Pantheon, and in it he made the church of the ever-virgin St Mary and all martyrs (S. Mariae ad martyres); in this church the emperor presented many gifts.”11 Although the original purpose of the Pantheon is still subject to discussion, in the Early Middle Ages, obviously, the Pantheon was known as a “temple” (templum).12 If indeed the Pantheon originally served as a temple, architectonically it was not a temple in the conventional sense, a fact that may have facilitated its conversion into a church.13

Medieval liturgical calendars make it clear that the Christian consecration of the Pantheon took place on a May 13, although the exact year of the consecration has remained uncertain. It has therefore been suggested that if the consecration of the Pantheon took place on a Sunday during Boniface’s papacy, it would have had to occur on May 13 of 613. Yet it does not seem to have been required by the Roman Church that consecrations took place on Sundays.14 It is therefore possible that the Pantheon was consecrated no later than 610, at which time Emperor Phocas was still alive and able to present the newly consecrated church with gifts, as recorded by the Liber Pontificalis. Since Boniface was elected pope in August 608 and the consecration of the Pantheon took place in the month of May, only the years 609 and 610 are plausible dates. There is no further evidence, however, in favor of one of these years over that of 613. Nevertheless, in order to narrow it down, the consecration of the Pantheon has sometimes been associated with the placement of the Column of Phocas on the Forum Romanum. In the month of August 608, this column was set up by the Byzantine exarch of Italy to honor the Byzantine emperor and his newly achieved one-year truce with the Longobards, who had threatened Rome with invasion. According to this hypothesis, the emperor’s concession of the Pantheon to the Church might have taken place in this new, albeit short-lived, moment of reconciliation and peace. If so, it is likely that Phocas reacted promptly, that is, in 609 rather than in 610, and that the Pantheon was consecrated within that same year.15

The collective dedication of the Pantheon to “all the martyrs” meant that the annual celebration of S. Mariae ad martyres on May 13 also became the origin of the Roman feast in honor of all saints.16 As the English historian the Venerable Bede (673?–735) declared about a century later, the collective dedication was aimed at replacing the earlier dedication of the building to the pantheon of the pagan gods and thus at substituting saints for demons, a claim that was repeated throughout the Middle Ages.17 The oft-repeated story that Pope Boniface had 28 cartloads of martyrs’ bones transferred here from the catacombs outside the walls of Rome was probably invented during the Counter Reformation a millennium later than the Christian consecration, and bears little resemblance to the seventh-century cult of relics in Rome.18

In the beginning, the Pantheon was simply recorded in liturgical sources as ad martyres, but already by the mid seventh century, the Sanctae Mariae ad martyres, as it officially appeared in administrative sources after 650, was becoming dominant. From the second half of the eighth century, the Pantheon was also called by its unofficial nickname, Sanctae Mariae Rotundae.19 Whereas the dedication of the building to all the martyrs may be equated with that of all the pagan gods in the ancient Pantheon, the additional dedication to the Virgin is puzzling. The Virgin Mary was, of course, not a martyr, and was already honored in the dedications of many older churches in Rome, such as S. Maria Maggiore, S. Maria in Trastevere, and S. Maria Antiqua.20

The best-known medieval guidebook to the city of Rome, the Mirabilia Urbis Romae, compiled circa 1140 by Benedict, a canon of St. Peter’s, claims that the dedication to the Virgin replaced the original one to Cybele, considered the mother of all the ancient gods.21 Be that as it may, the Christian dedication to the Virgin may well be associated not with Cybele but with the circular shape of the Pantheon. Until the conversion of the Rotunda, there was no Marian church in Rome with a centralized plan. Although frequently associated with Marian dedications in the early modern period, centralized memorials (memoriae) dedicated to the Virgin Mary were common in the eastern part of the Christian world from the fifth century on. Perhaps the most famous was the Chapel of the Hagios Soros in Constantinople. From the early seventh century, this well-documented chapel seems to have been among the main sanctuaries of the Byzantine capital, probably housing important Marian relics, such as the belt and shroud that she had left behind when she ascended to heaven. This no-longer extant chapel was circular and seems to have been domed. It was preceded by an entrance hall (narthex) and terminated on the opposite side with an apse. Since at the time of the consecration of the Pantheon Rome was under strong Byzantine influence, it seems possible that the idea of dedicating a circular sanctuary to the Virgin was imported from the East, and that Hagios Soros in Constantinople may have served as an immediate source of inspiration.22

Unlike the Byzantine prototype, the Pantheon could boast no relics to evoke the presence of the Virgin Mary within its sanctuary. On the other hand, the Rotunda possessed another kind of sacred object that evoked the Virgin’s presence just as strongly as did a relic, that is, an icon (Fig. 8.1). The image, partially broken but still preserved inside the Pantheon, presents the Virgin dressed in a maphorion, holding the Child in her left arm while pointing to him with her right.23 The icon is first mentioned in an episode that occurred during Stephen III’s pontificate (768–772). The Lombard priest Waldipert, who had failed in a plot against the Romans, took refuge in the Pantheon where he held tenaciously to the “image of God’s mother” to save himself from murder at the hands of the Romans who pursued him.24 The icon does not appear in earlier written sources, but is sometimes believed to have been produced as early as the period of the Christian consecration of the Pantheon, although this cannot be proven on technical grounds. Such an early dating would make the icon one of the oldest in Rome and the only “temple” image directly related to the consecration of the sanctuary where it would take up residence. Other venerable Marian icons in Rome that probably date to the late sixth and seventh centuries include the so-called Salus Populi Romani from S. Maria Maggiore, and the Madonna of S. Maria Nuova, originally from S. Maria Antiqua, a remodeled ancient building in the Roman Forum. Both churches were among the oldest Marian sanctuaries in Rome, dating respectively to the early fifth and sixth centuries and thus predating the installation of their icons.25

8.1. Madonna and Child icon from the Pantheon, seventh century? (Bibliotheca Hertziana – Max-Planck-Institut für Kunstgeschichte, Rome)

The Christianized Pantheon may thus have fused the eastern practice of dedicating centralized sanctuaries to the Virgin Mary with the idea – which seems to have become Roman practice in the late sixth or seventh centuries – of providing a Marian church with an icon of the Virgin and Child. At the Pantheon, the icon would thus have served as the equivalent for the important contact relics of the Virgin in the Constantinopolitan Soros church. It is possible, however, that the Marian icon was not installed until sometime after 650 when the church changed its official name from the generic designation ad martyres, to Sanctae Mariae ad martyres. The explicit emphasis on the Virgin Mary in the new dedication may thus be attributable to the arrival of the icon. From the second half of the eighth century, the circular shape of the church was embodied in the popular name, Sanctae Mariae Rotundae, which became its official name by the beginning of the twelfth century.26

The Pantheon as Source

The architectural uniqueness of the Pantheon meant that the building became a popular source of inspiration for medieval builders. Although it was impossible to emulate its revolutionary construction techniques, which had been lost, the basic design of the Rotunda – a circular plan with enveloping niches topped by a dome – permeates several Late Antique imperial mausolea and early medieval churches across and beyond Europe. Close “academic” copies of the Pantheon can be seen in the mausolea at Maxentius’s Circus (307–312) on the Via Appia and in that of the Tor de’Schiavi (c. 300) on the Via Prenestina in Rome (Fig. 8.2). Other examples inspired by the Rotunda include the fourth-century imperial mausolea of Helena and Constantina. Moreover, matching the Roman prototype in form is Constantine the Great’s domed rotunda of the Holy Sepulchre in Jerusalem marking the site of Christ’s tomb and Resurrection.27

8.2. Exterior of Mausoleum of Tor de’Schiavi, Rome, c. 300. (Bibliotheca Hertziana – Max-Planck-Institut für Kunstgeschichte, Rome)

Toward the end of the seventh century, the English churchman and pilgrim to Rome Wilfrid built a circular church at Hexham, now known only through written sources. Since the church with its unusual circular plan was also dedicated to the Virgin, there can be little doubt that it was ultimately modeled on the Pantheon, the only important circular Marian church in Rome. The English example points to the Pantheon – Santa Maria Rotonda – as the prototype for many later medieval centrally planned churches in the West dedicated to the Virgin.28 An interesting centralized building, which both as a Late Antique mausoleum and Marian church becomes linked to the Pantheon, is Theodoric the Great’s early sixth-century mausoleum in Ravenna, Italy (Fig. 8.3). In the mid ninth century, the tomb of the Ostrogothic king was transformed into a church and explicitly named “Sancta Maria Rotunda.” By the middle of the eleventh century, it was referred to as “the basilica of St. Mary which is shaped in the likeness of the Roman Pantheon.”29In reality, the centralized mausoleum is a polygonal, two-storied building with walls encircled by niches and topped by a huge monolithic stone shaped as a dome. The fact that the mausoleum was polygonal, crowned by a dome, and incorporating niches all around was enough to recall the Pantheon. The same features characterize several chapels of the Carolingian period, all of them dedicated to the Virgin Mary in the “likeness” of the great Roman prototype.30

8.3. Exterior of Theodoric’s Mausoleum in Ravenna, early sixth century. (Deutsches Archäologisches Institut, Rome)

The Pantheon thus served as the generic source for a vast number of centralized Marian sanctuaries throughout medieval Europe. This reception is indicative of the exceptional monument that it was. To be sure, its uniqueness derived not only from its circular plan and dome but primarily from its being the Pantheon, an ingenious and stunning example of ancient architecture that overshadowed all later buildings. The Golden Legend (Legenda aurea) provides a glimpse of the medieval perception of this monument; according to this thirteenth-century compilation of readings on the saints, the Pantheon was a “temple higher and more marvelous than the rest.”31

Inside Santa Maria Rotonda

The Pantheon suffered surprisingly few alterations in its conversion to new use. The cylindrical space absorbed its new religious functions without any serious alterations of the layout by Hadrian’s architects; it was not compromised by any inner divisions nor was its function or original north–south axis reoriented.

Such a smooth transition, accompanied by only minor structural changes, comes as less of a surprise in cases like the Forum churches of Ss. Cosmas and Damian, a former secular hall the original function of which remains unknown; S. Maria Antiqua, a former ceremonial hall providing entrance to the Palatine Hill; and S. Adriano, the former senate house (Fig. 8.4). The principal structure of each of these churches comprised a rectangular, fully covered hall.32 The latter was able to accommodate and serve the same functions as the basilica, the preferred building type adapted by Christians for their places of worship, as exemplified by Old St. Peter’s. We may therefore wonder if the unique space of the Pantheon was as easy to adapt as was that of the three churches on the Forum. Was there any question, for instance, about where to locate the altar inside the circular space? And were there any precedent cases of circular churches in Rome that could have served as models?

8.4. Exterior of S. Adriano, the former Roman Curia, Rome. (Deutsches Archäologisches Institut, Rome)

Despite the enormous success of the ancient basilica form for accommodating Christian worship, it was indeed not the only type of church plan in use. Two circular churches had in fact been built before the conversion of the Pantheon. The first was S. Stefano al Monte Celio, also known as S. Stefano Rotondo, dedicated by Pope Simplicius (468–483), with a circumference almost as large as the Pantheon’s (Fig. 8.5). Although S. Stefano Rotondo probably served as the local model that legitimized the circular plan for Christian use, no exact records have survived testifying to the original location of the altar.33

8.5. Interior of S. Stefano Rotondo, Rome. (Bibliotheca Hertziana – Max-Planck-Institut für Kunstgeschichte, Rome)

Whereas S. Stefano was built ex novo as a church, the other much smaller circular church predating the conversion of the Pantheon was originally an ancient mausoleum associated with the cemetery where the Apostle Peter was buried. Pope Symmachus (498–514) transformed the building, which had served as an annex to Old St. Peter’s, into a separate church dedicated to St. Andrea. Reminiscent of the Pantheon, the circular space of S. Andrea was surmounted by a dome, and the surrounding wall was pierced by seven niches (Fig. 8.6). As documented by Sible De Blaauw, the main altar, dedicated to St. Andrew, was placed in the eastern niche directly opposite the entrance and provided with an altar canopy (ciborium). Altars were originally installed in four of the other niches, whereas the remaining two were “filled” only in the eighth century.

8.6. S. Andrea, with chapels labeled, attached to Old St. Peter’s. (Sible De Blaauw, Cultus et Decor. Liturgia e architettura nella Roma tardoantica e medievale, Vatican City 1994, Fig. 19)

Like S. Andrea (Fig. 8.6, A1), the church of Santa Maria Rotonda also had the main altar situated directly opposite the entrance in the main exedra where Hadrian’s throne had presumably once stood. Indeed, in contrast to the alternating rectangular and semicircular exedras, the main exedra in Hadrian’s rotunda had already been emphasized by two Corinthian columns projecting into the central space. In this way, the original main axis of the building – from the barrel-vaulted entrance corridor to the principal exedra inside the rotunda – proved amenable to the new Christian context. As for the lateral niches, shortly before the middle of the ninth century the Carolingian poet and biblical exegete Walafried Strabo (c. 808–849) recorded that the Pantheon was a church with altars oriented in “all directions of the wind.”34 This certainly suggests the placement of side altars in the lateral exedras. If so, S. Andrea may have served as the direct model for this arrangement, which may be datable to the time of the Christian consecration of the Pantheon.35

On account of its importance as the backdrop for the main altar and the celebration of the Mass, the half dome of the main apse was decorated in a fittingly Christian manner, with a mosaic showing a cross in the center similar to the apse mosaic commissioned by Pope Theodore (642–649) for the church of S. Stefano Rotondo (Fig. 8.7). Since the remains of this mosaic were recorded only in the late sixteenth century, we cannot be certain that it dates back to the time of the Christian consecration, though it seems probable.36

8.7. Apse mosaic of S. Stefano Rotondo. (Alinari 1941)

We also know that the main altar of the Pantheon was placed under a ciborium of silver and covered by a precious purple cloth (coopertorium) donated by Pope Benedict II (684–685). About a century later, Pope Hadrian I (772–795) restored the ciborium, which, as his contemporary biography states, “had been worn away by age,” and fifty years later the same canopy was completely replaced.37 The practice of adorning an altar with a precious canopy and replacing it periodically appears to have been common, and in the case of S. Andrea, the genealogy of the canopy can be traced back to the consecration of the church in the early sixth century.38 Hence, the main altar in Santa Maria Rotonda may also have received its first ciborium at the time of its consecration around 609.

Also dating back to the year 609 may have been a large rectangular podium nearly 1 meter high, on which the altar was placed (see Fig. 9.6 and Plate V). Descriptions and drawings from the seventeenth century allow us to reconstruct the original situation with some precision.39 The podium, which was renovated by Pope Innocent VIII (1484–1492), filled the apse and extended some 7 meters into the central space. Surrounding it on all three of its freestanding sides was a pergola: a parapet of marble and porphyry plates separated by six porphyry columns carrying an architrave. The podium could be accessed from the front through the central intercolumniation. The altar, surmounted by its canopy supported by four porphyry columns, was placed on the chord of the apse. The back and sides were covered with porphyry plates, while the front was pierced by a so-called fenestrella, a window through which one could peer into the interior of the altar. Such an arrangement suggests the presence of relics inside the altar. Sources going back to the fifteenth century record the relics under the altar as those of the martyrs Rasius and Anastasius, and one of the reliquaries containing these relics records that Boniface himself deposited them there following a Roman tradition established by Pope Gregory the Great (590–604). These martyrs, however, appear neither in the medieval sources nor in the liturgical calendar of Santa Maria Rotonda. If the remains of these martyrs were buried under the main altar by Boniface himself, they evidently did not play an important role in the Christian worship related to the church.40

Several parts of the altar podium survive and are datable to the later Middle Ages, but the use of porphyry suggests an early medieval origin, as does the idea of an elevated podium in and in front of the apse and equipped with a pergola.41 Probably between 588 and 604, and thus just a few years prior to the conversion of the Pantheon, a similar altar arrangement had been designed for Old St. Peter’s to meet the requirements of the stational liturgy (see the last section of this essay).42 What would have been more natural than for Boniface VIII to have imitated the most recent and authoritative model of the altar of Old St. Peter’s for his new church in the Campus Martius?

Besides the altar arrangement resembling that recently developed for Old St. Peter’s, Santa Maria Rotonda also needed a choir to accommodate singers and lower-ranked clerics. Yet it is hard to imagine a choir situated in front of the altar podium since it would thus have nearly coincided with the area beneath the wide opening at the center of the dome, and thus have been unprotected against the rain, which is seasonally heavy in Rome.43 Any permanent solution for a choir inside Santa Maria Rotonda is therefore difficult to imagine. Another problem would have been designating a space to serve as a sacristy where the clergy could maintain their vestments and keep their liturgical utensils.

Santa Maria Rotonda from Outside

Before entering Santa Maria Rotonda, the medieval visitor would have observed a number of ancient statues in the piazza in front of its entrance hall. The Narracio de Mirabilibus Urbis Romae, written sometime during the thirteenth century by an otherwise unknown Magister Gregorius and related to the aforementioned Mirabilia Urbis Romae in that it also describes the topography and ancient monuments of Rome, is the earliest source to describe the following scenario: “It has a spacious portico, supported by many lofty columns, and in front of it remain to this day a basin and other wonderful porphyry vessels, as well as lions and other statues made of the same material.”44 Some of these statues seem to have been in place in front of the Pantheon from antiquity; others were probably added subsequently as spolia from ancient monuments.

Whereas the interior of the Pantheon was left basically untouched except for additions related to the accommodation of the altar, the exterior of the building underwent several important modifications over the course of time. Some of these were functional to the building itself, while others were less well intentioned, as in the case of the Byzantine emperor Constans II (641–668) who came to Rome on a pilgrimage in 663 and had the gilded bronze plates removed from the dome and shipped to Constantinople. This loss was to some extent compensated for in the eighth century when the roof of the cupola was lined with lead sheets.45 The spoliation of materials from the Pantheon is a reminder that its conversion to Christian purpose did not prevent its selective depredation.

Among the early embellishments added to the Christian building was a Latin cross set above the triangular gable surmounting the columned portico. According to a decree issued by Theodosius II in 435, this type of cross was to be erected in cases where a pagan cult building was being reused, as a means of exorcism. The cross of the Pantheon appears in a mural painting by Cimabue in the crossing vault of the choir in the Upper Church of San Francesco in Assisi (Fig. 8.8). The fresco, which dates to the late 1270s, shows the upper part of Santa Maria Rotonda as it appeared prior to this date, since it omits the bell tower (campanile) set up in 1270 on top of the gable that was demolished during Urban VIII’s pontificate (1623–1644). The year of the erection of the bell tower is recorded in an inscription on a stone tablet, still visible within the Pantheon portico. It is reasonable to assume that the cross was mounted on top of the gabled roof immediately following the conversion, and was done not only to follow the aforementioned decree of 435 but also to advertise the new Christian use of the building. It was removed in the sixteenth century.46

8.8. Detail of the Pantheon in a fresco by Cimabue, Upper Church of Assisi. (Kunsthistorisches Institut, Florence)

In fantastical medieval descriptions of the edifice, Santa Maria Rotonda was, moreover, surmounted by the famous Pigna; a medieval legend recounted in the Mirabilia Urbis Romae tells us that the Pigna, a huge ancient bronze pine cone that once stood in the atrium of Old St. Peter’s and can now be admired in the Belvedere Court of the Vatican Museum, was placed on top of Santa Maria Rotonda.47 Probably in conjunction with the placement of the cross on the portico gable, alterations were also made to the portico. All that survives today of these medieval modifications, which were obliterated in the seventeenth century, are eight holes in the shafts of the columns, and traces of cuttings into the six column bases (Fig. 8.9). From this exiguous evidence, and supported by the visual traces found in several drawings and prints, Michael Viktor Schwartz has offered a convincing hypothesis. According to Schwartz’s reconstruction, walls rising to a height of nearly 4.5 meters were built between the columns through which one previously entered the Rotunda. The three central openings at the front, however, were left open and turned into a rather impressive portico framed on either side by door frames and topped by entablatures. All the elements seem to have been of marble. The central opening was further monumentalized by being slightly taller and crowned by not one but two lintels, possibly forming a classicizing entablature consisting of an architrave and a cornice with an elaborately carved frieze at the center (Fig. 8.10). If so, perhaps these elements were originally part of another ancient building in Rome, possibly a temple, and reused as spolia in Santa Maria Rotonda, a practice common in church building in Rome and elsewhere throughout the Middle Ages as mentioned previously.48

8.9. Columns and shafts. (Bibliotheca Hertziana – Max-Planck-Institut für Kunstgeschichte, Rome)

8.10. Reconstruction drawing of medieval Pantheon facade based on elevation drawing of Antoine Desgodetz. (Bibliotheca Hertziana – Max-Planck-Institut für Kunstgeschichte, Rome)

Comparisons with several surviving monuments may help us to further envisage the no-longer extant medieval portico of the Pantheon. In Rome itself, the original portico of the Lateran Baptistery built by Pope Sixtus III (432–440) consists of two central porphyry columns creating three intercolumniations (Fig. 8.11). The middle of these forms a central portal created by cutting away parts of the column bases and adding jambs and a crowning carved entablature. Flanking this portal are two adjacent ones that are lower, but again with jambs supporting carved lintels. In contrast to the Pantheon, however, these openings are each fitted with two door-like marble plates. Throughout, the materials utilized in the Baptistery are reused marble spolia from other buildings. Thus, though both the overall design and the construction method strongly recall the Pantheon, the uncertain dating of the Lateran portico to a500-year period between the middle of the fifth and the tenth centuries undermines any attempt to specify when the original Pantheon portico could have been modified or what its models were.49 Only by looking to Constantinople do we find a viable prototype for the Pantheon portico, that is, the portico of the Studios Church, which dates to the fifth century. Here, analogously to the Pantheon, three intercolumniations create a portico comprising a central doorway and two lateral ones enriched by door frames that cut through the column bases and support a lavish entablature inserted between the columns (Fig. 8.12). It also seems that the central intercolumniation once held door frames that were later removed.50 As argued by Schwartz, Constantinople thus seems to have furnished the inspiration for the type of portico introduced at the Pantheon, and could have already done so during Pope Boniface’s pontificate when the Pantheon assumed its official new function as a church.51 Besides the interior of the Rotunda itself, the modified portico is the only space that could have accommodated a sacristy, but this possibility remains hypothetical since no trace of such a sacristy survives. As we shall see, it is in fact questionable whether Santa Maria Rotonda needed a sacristy at all.

8.11. Porch of Lateran Baptistery. (Bibliotheca Hertziana – Max-Planck-Institut für Kunstgeschichte, Rome)

8.12. Porch of Studios Church, Constantinople. (Dumbarton Oaks Research Library and Collection, Washington, DC)

Although the change to the original portico was modest in scale and did not affect the exterior of the Rotunda, it transformed the aspect of the ancient building in one significant way: whereas previously visitors could choose to enter the portico through the intercolumniations on its three sides, they were now limited to one of the three central ones, with the middle of the three being most conspicuous due to its height and decoration. In other words, accompanied by the cross on top of the gable and the much later bell tower, the medieval entrance hall gave extra emphasis to the main axis of the Rotunda as originally established by the barrel-vaulted vestibule in front of the great door. The impressive bronze doors, indeed, have always provided the only truly magnificent access to the splendid interior.52

Santa Maria Rotonda in Ritual Life

We may well wonder what prompted Pope Boniface to convert an ancient circular building into a church in the first place. To respond to this question, we must consider the role played by Santa Maria Rotonda in the liturgical calendar of medieval Rome.

Almost as unusual as its design was the status that Santa Maria Rotonda held within the city’s ritual life. It was neither a presbytery church nor a diaconia (a church where food to the poor was distributed), and thus had neither a clergy nor a congregation of its own. Instead, it was made a stational church, that is, one in which the pope held services on certain feast days during the liturgical year rather than in his cathedral.53 The days on which the pope held station service in Santa Maria Rotonda were January 1, Easter Friday, and May 13 (consecration day).54 For these station services, the pope arrived in the Campus Martius as part of a solemn procession that included the entire clergy of the Lateran, other clerics, and laymen.

The station services, which were introduced in the fifth century and increased in number until the twelfth, are best understood as a means of decentralizing the papal liturgy in the Lateran to encompass the other more populated areas of the city. Stational churches were thus extensions of the pope’s cathedral. By the beginning of the seventh century, the most important stational churches of Rome included the five so-called patriarchal basilicas of Rome (S. Giovanni in Laterano, S. Pietro, S. Paolo fuori le mura, S. Maria Maggiore, S. Lorenzo fuori le mura) and, secondary to these, the churches of Santa Maria Rotonda, S. Croce in Gerusalemme, SS. Apostoli, and S. Stefano Rotondo.55

Around the year 1100, the stational liturgy in S. Maria Rotunda underwent a change. The station of January 1 was transferred to S. Maria in Trastevere and replaced by the Dominica de Rosa, a new station service that fell on the Sunday between Christ’s Ascension and Pentecost. The purpose of this Sunday was to announce the coming of the Holy Spirit on Pentecost. In the Pantheon, this event was visualized in a spectacular way: while the priest in his sermon announced the arrival of the Holy Spirit, the latter was symbolized by a multitude of roses that were dropped into the church from the top of the cupola. Whether or not the roses actually came down through the oculus, they certainly contributed significantly to the impression of a continuum between heaven and earth during this extraordinary happening.56

The decision to create the Pantheon as a stational church would have had several bases. First, the Campus Martius, after the decay of its public buildings, had slowly developed into one of Rome’s most densely populated districts, but had remained poor in terms of important church foundations. The conversion of the Pantheon, spacious and capable of accommodating the huge congregation that could be expected for a pontifical Mass, may thus be seen as a quick and efficacious way of giving the Roman Church a significant presence in one of the city’s most densely inhabited areas. As an extension of the pope’s cathedral at the Lateran, Santa Maria Rotonda brought the pope closer to the people of Rome. However, as a stational church, it was directly serviced by the papal administration, which meant that services were not held in the church on a regular basis. Thus, prior to the twelfth century, no priests or monks are recorded to have provided daily service in the church.57 This could also explain why the church may never have had a sacristy. In addition, the cupola’s huge open eye would have made regular service rather uncomfortable at times; aside from rain that kept the faithful from standing in the center of the church, the opening in the dome would have rendered the space both damp and chilly during the winter season. Clearly, as long as the open eye was not closed – which it never was – the Pantheon was not really a suitable building for daily services. Quite simply, it did not work as an ordinary church. But precisely because of the shortcomings entailed by its unique architectural form, Santa Maria Rotonda was all the more magnificent as a setting for the pope’s occasional appearances in the center of medieval Rome.

1 Corpus Inscriptionum Latinarum (CIL), ed. Matthaeus della Corte, vol. 6, Berlin 1970, p. 896; Kjeld de Fine Licht, The Rotunda in Rome: A Study of Hadrian’s Pantheon, Copenhagen 1968, p. 180.

2 Sextus Iulius Africanus, Cesti: the Extant Fragments, ed. Martin Wallraff, trans. William Adler, Berlin 2012, pp. 63–68; Licht 1968, pp. 183, 237–238.

3 Ammianus Marcellinus, Rerum gestarum libri, fourth century AD, ed. J. C. Rolfe, Cambridge 1956, pp. 249–250; J. B. Ward-Perkins, From Classical Antiquity to the Middle Ages: Urban Public Building in Northern and Central Italy, AD. 300–850, Oxford 1984, p. 39.

4 On the Christianization of Rome, see Richard Krautheimer, Rome – Profile of a City, 312–1308, Princeton 1980, pp. 33–58; Torgil Magnuson, The Urban Transformation of Medieval Rome, 312–1420, Stockholm 2004, pp. 51–64; Hugo Brandenburg, Ancient Churches of Rome from the Fourth to the Seventh Century, Turnhout 2005, pp. 16–36, 91–103.

5 Christian Hülsen, “Delle vicende del Pantheon nell’ultima età imperiale,” Bulletino della Commissione Archeologica Comunale di Roma 54, 1927, pp. 64–66.

6 Magnuson 2004, pp. 64–67. On the urban transformation of early medieval Rome, see also Roberto Meneghini and Riccardo Santangeli Valenzani, Roma nell’altomedioevo. Topografia e urbanistica della città dal V al X secolo, Rome 2004, and on the formidable display in the Crypta Balbi Museum just off Largo Argentina in the center of Rome, see Daniele Manacorda, Crypta Balbi. Archeologia e storia di un paesaggio urbano, Milan, 2001.

7 Licht 1968, p. 186.

8 Procopius of Caesarea, The Story of the Wars, “The Gothic War,” IV 22, 5–6, trans. H. B. Dewing, Cambridge 1924; repr. 2000, p. 5; Ward-Perkins 1984, p. 47.

9 William L. MacDonald, The Pantheon: Design, Meaning and Progeny. London 1976, repr. 2002, p. 18.

10 For summaries of the history of the Pantheon in the Middle Ages, see Christian Hülsen, Le Chiese di Roma nel medioevo, Florence 1927, p. 363; S. B. Platner, A Topographical Dictionary of Ancient Rome, ed. Thomas Ashby, Oxford 1929, p. 385; VittorioBartoccetti, Santa Maria ad Martyres, Rome 1958; Ernest Nash, Bildlexikon zur Topographie des antiken Rom, Tübingen 1962, vol. 2, pp. 170–175; Licht 1968, pp. 237–240.

11 The Book of Pontiffs (Liber Pontificalis): The Ancient Biographies of the First Ninety Roman Bishops to AD 715, trans. Raymond Davis, Liverpool 1989, p. 62 (translation of Liber pontificalis, ed. Louis Duchesne, 3 vols.; vol. 1, Paris 1886; vol. 2, Paris 1892; vol. 3 ed. Cyrill Vogel, Paris 1957); Caecilia Davis-Weyer, “S. Stefano Rotondo in Rome and the Oratory of Theodore I,” Italian Church Decoration of the Middle Ages and Early Renaissance, ed. William Tronzo, Bologna, 1989, p. 62. On this source, see most recently Herman Geertman (ed.), Il Liber Pontificalis e la storia materiale, Assen 2003. The dedication is also mentioned by Paul the Deacon, History of the Lombards, trans. William Dudley, Philadelphia 1974, pp. 177–178, and repeated by John the Deacon,Chronicon Venetum, I, 21, ed. and trans. Luigi Andrea Berto, Bologna 1999. On Pope Boniface and the consecration of the Pantheon, see Mirella Colucci, Bonifacio IV (608–615): momenti e questioni di un pontificato, Rome 1976, pp. 25–37; see also FerdinandGregorovius, Geschichte der Stadt Rom im Mittelalter, ed. Waldemar Kampf, 7 vols., Munich 1978; vol. 1, pp. 286–290.

12 Paul Godfrey and David Hemsoll, “The Pantheon: Temple or Rotunda?” Pagan Gods and Shrines of the Roman Empire, ed. Martin Henig et. al., Oxford 1986, pp. 195–209.

13 On the transformation of temples to churches in the Christian East and West, see Friedrich Wilhelm Deichmann, “Frühchristliche Kirchen in antiken Heiligtümern,” Jahrbuch des Deutschen Archäologischen Instituts 54, 1939, pp. 105–136; Brandenburg 2005, pp. 233.

14 For the earliest source mentioning the dedication on a May 13, see Theodor Klauser, Das römische Capitulare Evangeliorum, 2nd ed. Münster 1972, p. 73; in favor of 613 are Herman Geertman, More Veterum. Il Liber Pontificalis e gli edifici ecclesiastici di Roma nella tarda antichità e nell’alto medioevo, Groningen 1975, p. 226, n. 135.1; Sible De Blaauw, “Das Pantheon als christlicher Tempel,” Bild und Formensprache der spätantiken Kunst. Hugo Brandenburg zum 65 Geburtstag, Münster 1994, pp. 13–26; however, he does call attention to the fact that the dedication did not necessarily have to happen on a Sunday.

15 Francesco Gandolfo, “Luoghi dei santi e luoghi die demoni: Il riuso dei templi nel Medioevo,” Santi e demoni nell’alto medioevo occidentale, 2 vols., Spoleto 1989; vol. 2, pp. 883–916. Martin Wallraff, “Pantheon und Allerheiligen,” Jahrbuch für Antike und Christentum, 47, 2004 (appeared 2006), pp. 128–143; for the column of Phocas, see Franz Alto Bauer, Stadt, Platz und Denkmal in der Spätantike, Mainz 1996, pp. 43–47. For Pope Boniface and Emperor Phocas, see Colucci 1976, pp. 77–87.

16 Pierre Jounel, Le culte des saints dans les basiliques du Latran et du Vatican au douzième siècle, Rome 1977, pp. 103–106; De Blaauw 1994b, p. 14; Wallraff 2004, pp. 139–140, relates the May 13 dedication date to the feast day of all martyrs in Syria.

17 Venerable Bede, “Chronica,” in Chronica Minora, ed. Theodor Mommsen, 3 vols., Monumenta Germaniae Historica, Berlin 1892–1898; vol. 3, pp. 309–310. Gandolfo 1989, p. 899; Tilmann Buddensieg, “Criticism and Praise of the Pantheon in the Middle Ages and the Renaissance,” Classical Influences on European Culture A.D. 500–1500: Proceedings of an International Conference Held at Kings College, Cambridge, April 1969, ed. R. R. Bolgar, Cambridge 1971, pp. 259–267; Wallraff 2004, pp. 139–140.

18 Susanna Pasquali, Il Pantheon: architettura e antiquaria nel Settecento a Roma, Modena 1996, pp. 24–25; she attributes the story to Cardinal Cesare Baronio in 1586 on p. 215. See also Pietro Lazeri, Della consecrazione del Pantheon fatta da Bonifazio IV, Rome 1749, p. 24. On relic translations in early medieval Rome, see J. M. McCulloh, “From Antiquity to the Middle Ages. Continuity and Change in Papal Relic Policy from the 6th to the 8th Century,” in E. Dassmann and K. Suso Frank, eds., Pietas: Festschrift für Bernhard Kötting, Münster 1980, pp. 313–324; Alan Thacker, “Rome of the Martyrs: Saints Cults and Relics, 4th–7th Century,” in Roma Felix: Formation and Reflections of Medieval Rome, ed. Eamonn O’Carragain and Carol Neuman de Vegvar, Aldershot 2007, pp. 13–49.

19 For ad martyres, see Geertman 1975, p. 137; for Sanctae Mariae ad martyres, see, for instance, Duchesne 1886–1957, vol. 1, p. 343; Davis-Weyer 1989, p. 72; for Sanctae Mariae Rotundae, see Geertman 1975, p. 136. See De Blaauw 1994b, p. 14.

20 For these churches, see Richard Krautheimer, Corpus basilicarum christianarum Romae, Vatican City, 1937–1977, 5 vols.; vol. 3, pp. 1–60, 65–71; vol. 2, pp. 249–268; Brandenburg 2005, pp. 112–113, 176–189, 224–232.

21 For the text of the Mirabilia, see Roberto Valentini and Giuseppe Zucchetti, Codice Topografico della Città di Roma, vol. 3, Rome 1946, pp. 3–65. See also Morgan Nichols, trans., The Marvels of Rome (Mirabilia Urbis Romae), 2nd ed. New York 1986, p. 22. On this source, see Dale Kinney, “Fact and Fable in the Mirabilia Urbis Romae,” in O’Carragain and Neuman de Vegva 2007, pp. 235–253.

22 Richard Krautheimer, “Sancta Maria Rotunda,” in Arte del primo millennio, ed. Edoardo Aslan, Turin 1953, pp. 21–27. For the centralized church and its symbolic relationship to the Virgin Mary in the Middle Ages and Renaissance, see RudolfWittkower,Architectural Principles in the Age of Humanism, 4th ed. rev., New York 1988, p. 40; Staale Sinding Larsen, “Some Functional and Iconographical Aspects of the Centralized Church in the Italian Renaissance,” Acta ad Archaeologiam et Artium Historiam Pertinentia 2, 1965, pp. 203–252.

23 Carlo Bertelli, “La Madonna del Pantheon,” Bolletino d’arte 46, 1961, pp. 24–32; S. Ensoli and E. La Rocca, Aurea Roma: dalla città pagana alla città cristiana, Rome, 2000, pp. 661–662 (no. 376).

24 Duchesne 1886–1957, vol. 1, p. 472; Raymond Davis, trans., The Lives of the Eighth-Century Popes (Liber Pontificalis), Liverpool 1992, p. 95.

25 Hans Belting, Likeness and Presence: A History of the Image before the Era of Art, Chicago 1994, pp. 121–122; Gerhard Wolf, Salus Populi Romani. Die Geschichte römischer Kultbilder im Mittelalter, Weinheim 1990, pp. 128–130; Erik Thunø, “The Cult of the Virgin, Icons and Relics in Early Medieval Rome A Semiotic Approach,” Acta ad archaeologiam et artium historiam pertinentiam 27, 2003, pp. 79–101.

26 J. Von Pflugk-Harttung, ed., in Acta pontificum romanorum inedita, 3 vols., Stuttgart 1888, vol. 3, p. 123; De Blaauw 1994b, pp. 14, 25–26. See also Theodor Klauser, “Rom und der Kult der Gottesmutter Maria,” Jahrbuch für Antike und Christentum 15, 1972, pp. 120–135.

27 Richard Krautheimer, Early Christian and Byzantine Architecture, 4th rev. ed, Hammondsworth 1986, pp. 60–64; J. B. Ward-Perkins, Roman Imperial Architecture, rev. ed., London 1994, pp. 424–426; Charles B. McClendon, The Origins of Medieval Architecture, New Haven 2005, pp. 8, 72; Brandenburg 2005, pp. 60–63, 73–78.

28 McClendon 2005, pp. 70–72.

29 Krautheimer 1953, p. 21; Krautheimer 1986, pp. 269–273.

30 Krautheimer 1953, pp. 21–22. As examples of such, Krautheimer mentions a chapel at Centula (790–799), one at Würzburg (780), one at Altötting near Munich (877), and one, also from the ninth century, at Ludwigstadt. See also McClendon 2005, pp. 154–155.

31 Jacobus De Voragine, The Golden Legend: Readings on the Saints, trans. William Granger Ryan, 2 vols., Princeton 1993; vol. 2, 272.

32 On these churches, see Krautheimer 1937–1977, vol. 1, 137–143; vol. 2, pp. 249–268; Brandenburg 2005, 222–234. On the Forum Romanum and its early medieval churches, see Bauer 1996, pp. 62–72; Meneghini and Santangeli Valenzani 2004, pp. 157–175.

33 De Blaauw, 1994b, pp. 16–17, who – like Davis-Weyer before him – assumes that the altar was placed in the southwestern part of the central space of the church; Davis-Weyer 1989, pp. 61–81, esp. 77–78; Brandenburg 2005, pp. 200–213.

34 Walafried Strabo, “De ecclesiasticarum rerum exordiis et incrementis,” in Capitularia regum francorum, legum sectio II, ed. Alfred Boretius and Viktor Krause, Monumenta Germaniae Historica, 2 vols., Hannover 1883–1897; vol. 2, p. 478; De Blaauw1994b, p. 20.

35 De Blaauw 1994b, pp. 15–19. See also Sible De Blaauw, Cultus et Decor. Liturgia e architettura nella Roma tardoantica e medievale, Vatican City 1994, pp. 466–470.

36 De Blaauw 1994b, p. 19. On the S. Stefano Rotondo mosaic, see Davis-Weyer 1989, pp. 61–81; Giuseppe Basile, “Il restauro del mosaico di S. Stefano Rotondo a Roma,” Arte medievale, 2nd ser., no. 1, 1993, pp. 197–204.

37 Duchesne 1886–1957, vol. 1, pp. 363, 514; vol. 2, pp. 83; Davis trans. 1992, p. 172.

38 Duchesne 1886–1957, vol. 1, p. 261; De Blaauw 1994b, p. 18.

39 De Blaauw 1994b, p. 22; Pasquali 1996a, p. 41.

40 Antonio Muñoz, “La decorazione medioevale del Pantheon,” Nuovo bulletino di archeologia cristiana, 18, 1912, pp. 25–35; De Blaauw 1994b, pp. 21–25; see also Tod A. Marder, “Specchi’s High Altar for the Pantheon and the Statues by Cametti and Moderati,” Burlington Magazine, 122, 1980, pp. 30–40.

41 Sible De Blaauw, “Papst und Purpur. Porphyr in frühen Kirchenausstattungen in Rom,” Tesserae, Festschrift für Josef Engemann, Münster 1991, pp. 36–51.

42 De Blaauw 1994a, vol. 2, pp. 530–556.

43 John Patrick Donnelly, “To Close a Giant Eye: The Pantheon, 1591,” Archivium Historiae Pontificiae 24, 1986, pp. 377–384.

44 For the text of the Mirabilibus, see Valentini and Zucchetti 1946, pp. 137–167, esp. pp. 158–159; Master Gregorius, The Marvels of Rome, trans. with commentary by John Osborne, Toronto 1987, pp. 29–30, 76–79, including a critical commentary on the statues mentioned by Gregorius.

45 Duchesne 1886–1957, vol. 1, pp. 343; vol. 2, p. 419; Paul the Deacon repr. 1974, pp. 223–224; John the Deacon repr. 1999. See also Frank G. Moore, “The Gilt Bronze Tiles of the Pantheon,” American Journal of Archaeology 3, 1899, pp. 40–43; P. Tomei, “Le vicende del rivestimento della cupola del Pantheon,” Bollettino d’arte 32, 1938, pp. 31–39.

46 Michael Viktor Schwarz, “Eine frühmittelalterliche Umgestaltung der Pantheon-Vorhalle,” Römisches Jahrbuch der Bibliotheca Hertziana 26, 1990, pp. 1–29, especially pp. 8–10. For the inscription concerning the campanile, see Licht 1968, pp. 240, 312 (n. 10).

47 Valentini and Zucchetti 1946, p. 45; Nichols 1986, p. 37. See also Noberto Gramaccini, Mirabilia. Das Nachleben antiker Statuen vor der Renaissance, Mainz 1996, pp. 163–165.

48 Schwartz 1990, pp. 4–18. The literature on spolia is vast, but for a classic article and for the most recent contributions see, for instance, Arnold Esch, “Spolien: Zur Wiederverwendung antiker Baustücke und Skulpturen im Mittelalterlichen Italien,” Archiv für Kulturgeschichte 51, 1969, pp. 1–64; Dale Kinney, “The Concept of Spolia,” A Companion to Medieval Art, ed. Conrad Rudolph, Oxford 2006, pp. 233–252, with discussion of historiography and extensive bibliography.

49 Schwartz 1990, p. 19.

50 Schwartz 1990, p. 20. As other examples of the same type of portico, Schwartz also mentions one from the sixth or seventh century in the Church of S. Thekla in Asia Minor, and one from the sixth century in the Baptistery of Hagia Sophia (pp. 19–22). For the Studios Church, see also Krautheimer 1986, pp. 104–105; Thomas Mathews, The Early Churches of Constantinople: Architecture and Liturgy, University Park/London 1971, pp. 19–21, and Thomas Mathews, The Byzantine Churches of Istanbul, University Park 1976, pp. 143–158.

51 Schwartz 1990, p. 28. On “eastern” influence on the architecture of Rome in the sixth and seventh centuries, see Krautheimer 1980, pp. 89–108; Krautheimer 1986, pp. 268–273.

52 Doris Gruben and Gottfried Gruben, “Die Türe des Pantheon,” Mitteilungen des Deutschen Archäologischen Instituts, Römische Abteilung 104, 1997, pp. 3–74.

53 Geertman 1975, pp. 132–142; De Blaauw 1994b, p. 14.

54 Geertman 1975, pp. 195–197; De Blaauw 1994b, p. 15. On stational liturgy in Rome, see also John F. Baldovin, The Urban Character of Christian Worship, Rome 1987, and Magnuson 2004, p. 73.

55 De Blaauw 1994b, 14–15; Krautheimer 1980, pp. 57–58.

56 Louis Duchesne and Paul Fabre, eds., Le Liber Censuum de l’Eglise, 3 vols., Paris 1910; vol. 2, pp. 157; De Blaauw 1994b, p. 15.

57 De Blaauw 1994b, p. 15.

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