Reviving Antiquity with Granite: Spolia and the Development of Roman Renaissance Architecture

Abstract

Ancient granite columns have been a pervasive element in the architecture of Rome since the Imperial era. However, in the fifteenth century, just as the effort to revive Antiquity intensified, these ubiquitous and durable ancient columns fell out of use. It was instead the stone travertine that became the columnar material of choice. Yet, just as quickly as this change occurred, within an exceptionally short period of thirty years, beginning with the construction of the Palazzo della Cancelleria courtyard, Rome saw a renascence in their application. While little has been made of this material shift, this article argues that the sudden extensive employment of spoliated granite columns was a crucial component in the recovery of a distinctly local Roman Antiquity. It was through the use and transformation of spolia that builders and patrons attempted to create an architecture that not only recalled Antiquity, but resubstantiated it, literally making it whole again.

Since being imported by ancient emperors, granite columns have been a pervasive element in the architecture of Rome. They adorned ancient baths and porticos, lined the naves of early-Christian basilicas, and were reused throughout the Middle Ages. However, in the second half of the fifteenth century, just as the effort to revive Antiquity intensified, these ubiquitous and durable ancient columns played only a minor role in that revival. It was instead the local, more workable stone travertine that became the columnar material of choice. Yet, just as quickly as this change had occurred, Roman builders once again turned to an interest in hard ancient granite columns. Within an exceptionally short period of thirty years, starting with the construction of the Palazzo della Cancelleria courtyard in 1496, Rome saw a renascence in their application. Little has been made of this material shift since formal innovations tied to the revival of Antiquity have often taken scholarly precedence over questions of materiality and reuse. But rather than simply being an afterthought of that revival, the sudden extensive employment of large granite columns was a crucial component in the recovery of a distinctly local Roman Antiquity. It signalled a new mode of architectural revival in Rome, in which spoliation displaced imitation with ancient granite columns being appropriated, not just to renew Antiquity, but to physically resubstantiate it.

GRANITE AND ROME

In the classical world, granite was highly valued by the Romans, who, after the establishment of the Empire, extensively exploited it for monolithic columns. ¹ Through a system of imperial quarries, Egyptian grey and red granite, and to lesser extent granite quarried in Turkey and on the islands of Elba and Giglio, became an integral part of the Roman language of monumental architecture. ² The predominant use of large granite columns in Rome, where they were erected by the thousands and adorned some of city's most spectacular buildings, including the Pantheon, the Forum of Trajan and the Baths of Caracalla and of Diocletian, made them a hallmark of the imperial capital. ³ Yet as the Roman marble industry declined in the third century CE, the quarrying of hard stones largely ceased. ⁴ Consequently, builders in Rome from late Antiquity onward came to reuse ancient granite columns for the construction of new buildings, a practice generally known since at least the early sixteenth century as spoliation. ⁵

That these architectural elements continued to be reutilised was not just a product of their ubiquity but also their durability. Egyptian granite was especially hard and resilient, and like other stones, once quarried, became even harder with time through a process known as case-hardening. ⁶ As Giorgio Vasari observed in the sixteenth century, not only was granite in the quarry ‘far softer and easier to work than after it has lain exposed’, but ancient granite columns due to their ‘hardness and solidity have nothing to fear from fire or sword, and time itself, that drives everything to ruin, not only has not destroyed them but has not even altered their colour’. ⁷ Granite, like porphyry, could only be carved through the use of special tempered chisels and with great effort. This method of hardening steel, which involved quenching red-hot metal and then tempering it, made tools strong enough to work even the hardest of stones. ⁸ Yet this process, developed in Antiquity, was largely lost during the Middle Ages. In medieval Rome, therefore, all that could be done to adapt granite columns was to shorten them or slice them into discs (like those found in Cosmatesque pavements) by means of saws and emery. ⁹

Despite this architectural limitation, granite columns were continuously reused throughout the medieval period, including in many early Roman churches such as St Peter's, S. Stefano Rotondo and S. Lorenzo fuori le Mura. In fact, over the course of the Middle Ages, the use of ancient granite columns became increasing prevalent and more churches, including S. Maria in Domnica, S. Prassede, S. Crisogono, S. Maria in Trastevere and SS. Quattro Coronati, exclusively employed columns of this type. ¹⁰ It was only in the later fifteenth century, just as the architectural revival of Antiquity gripped the city, that these columns fell out of favour. It was instead the travertine that became the material of choice for columnar architecture.

TRAVERTINE AND FIFTEENTH-CENTURY ROMAN ARCHITECTURE

The historiography of Roman Quattrocento architecture has often emphasised the emergence of a Renaissance aesthetic born out of both imported precedents and local ancient exempla. Yet this new Roman architecture was distinguished by not only its formal characteristics but also its material innovation, that is, its widespread embrace of travertine as a primary building material. Travertine, a white coloured sedimentary stone quarried in nearby Tivoli, had been a critical feature of the architecture of Republican and early Imperial Rome, being used most famously for the exterior of the Colosseum. ¹¹ Medieval Roman builders, however, rarely employed this stone as the principal material for monumental architecture, as brick and small blocks of tuff known as tuffelli often replaced large-scale ashlar construction. ¹² Nor did these same builders turn to travertine for columns, preferring instead spoliated marble and granite monoliths. While travertine remained in limited use in medieval Rome – it was employed in foundations and also burned for lime – it never became the preferred mural or columnar material, despite its availability.

It was only in the second half of the fifteenth century, with the consolidation of papal authority, an increase in architectural production and a renewed interest in the revival of Antiquity, that travertine re-emerged as a dominant Roman building material. As most, if not all, travertine employed during this period came directly from the monuments of Antiquity themselves – the Lombard contractor Giovanni Foglia, for example, transported over 2,500 cartloads of the stone from the Colosseum in just nine months during 1452 – travertine was intrinsically linked to the architecture of ancient Rome. ¹³ Building with travertine also literally meant building in the manner of the ancients with ashlar masonry. This not only required greater labour and resources but also skilled masons competent in squaring blocks of stone. In a city where the walls and façades of even the largest Christian basilicas were built primarily of brick, the use of travertine was a momentous shift, one that humanists even explicitly compared to the architectural achievements of Augustus. ¹⁴

The new-found importance of travertine is most evident in its conspicuous display in large palace and church façades, the latter including S. Maria del Popolo (begun 1472), S. Agostino (begun 1479) and S. Pietro in Montorio (begun 1483). ¹⁵ Its mutability also allowed architects of the period to go beyond basic mural construction and recreate countless antique-inspired forms, including all'antica round free-standing columns. Yet despite this potential, during the second half of the fifteenth century, Roman builders infrequently built with this type of column. ¹⁶ Rather, in many cases, they utilised octagonal columns constructed from multiple pieces of travertine, as in the exterior porticos of S. Pietro in Vincoli and SS. Apostoli (both begun c. 1475), the cloisters of S. Giovanni dei Genovesi (begun 1482; Fig. 1) and S. Cosimato (c. 1475), the courtyards of the Palazzetto of Palazzo Venezia (begun 1466; Fig. 2), Palazzo Nardini (begun c. 1473), Palazzo Domenico della Rovere (begun 1480s) and Palazzo Cesi (c. 1490s) and also the Cortile del Maresciallo at the Vatican (c. 1471). ¹⁷

Fig. 1. Rome, S. Giovanni dei Genovesi: cloister

Fig. 2. Rome, Palazzo Venezia: Palazzetto courtyard

The dominance of this distinctive non-monolithic ‘medieval’ column from the 1460s through to the 1490s in Rome appears as an aberration in the history of Renaissance architecture since it took hold just as the classically proportioned, cylindrical, monolithic column with entasis became ubiquitous throughout Italy. ¹⁸ Scholars, consequently, have often cast these columns as a provincial holdover or an economical solution. ¹⁹ Yet this ignores the fact they were also an essential component of a new architectural mode, one that was literally derived from the travertine-clad buildings of Antiquity. When travertine gained prominence in later fifteenth-century Rome, the octagonal brick colonnade, as seen at the cloister of S. Maria Nova (c. 1450; Fig. 3), the now-destroyed Palazzo Apostolico adjacent to S. Maria Maggiore (finished before 1452) and the heavily modified courtyard of the Palazzo Sforza-Cesarini (1458–62), simply underwent a transformation to travertine. ²⁰ It was the material of these columns rather than their form that evoked Antiquity.

Fig. 3. Rome, S. Maria Nova: cloister

At the same time, there were already attempts in fifteenth-century Rome to unite ancient form and material in a new mode of revival. The Benediction Loggia of S. Marco and the unfinished courtyard of the Palazzo S. Marco, both constructed under the aegis of Pope Paul II as part of the Palazzo Venezia complex during the second half of the 1460s, are early examples of this. Here, builders took travertine from the Colosseum – a fact noted in construction documents and later by authors such as Paolo Giovio, Giorgio Vasari and Alfonso Chacón – and transformed it through re-carving into compositions reminiscent of the Colosseum itself (Fig. 4). ²¹ This literal renewal of Antiquity, through the direct appropriation of ancient architectural form and its associated material in tandem, signalled a shift in the dynamics of revival in Renaissance Rome. It acknowledged that ancient materials, such as travertine, were tied to specific ancient forms, and also inaugurated a mode of revival I will term resubstantiation in which architects attempted to recover ancient architecture through the use of spolia and the joining of ancient form, material and technique.

Fig. 4. Rome, Palazzo Venezia: courtyard

This phenomenon, I propose, eventually led to the reassessment of the column in late fifteenth-century Rome. When the builders of the Palazzo S. Marco determined that travertine from the Colosseum should assume the form of that ancient monument, they abandoned the nearly contemporaneous courtyard model of the adjacent Palazzetto with its freestanding octagonal and round travertine columns (Fig. 2). This may suggest that travertine was no longer considered the most appropriate material for freestanding columns, that unlike the engaged column and arch, it did not have a strong ancient precedent. While the ancient Romans sometimes made freestanding columns from travertine, as seen in the Temple of Portunus, the Temple of Vesta at Tivoli and the temples at S. Nicola in Carcere and Largo Argentina, this practice largely ceased after the establishment of the Empire. By the fifteenth century, moreover, ancient travertine columns had mostly vanished, having been replaced with columns of coloured marble by later emperors, succumbed to the ravages of time, incorporated in later buildings or burned for lime.

The image of columnar Antiquity in Renaissance Rome was instead dominated by visions of monolithic columns carved of ancient hard stones such as granite and their spoliated medieval successors. It was this image that was manifested in numerous frescoes of fictive multi-coloured, veined columns painted in Rome from the 1470s onward. ²² It was also reiterated in the writings of humanists, who often highlighted porphyry, serpentine and granite columns in their descriptions of Rome. So pervasive was this view of ancient Rome that the author of the Antiquarie prospetiche Romane, a poem written in the late 1490s by an anonymous Milanese painter, augmented a brief description of the travertine-clad Colosseum by describing in detail an even grander imaginary circular building ringed with columns of porphyry, serpentine and alabaster. ²³

Ancient columns in late fifteenth-century Rome were defined not just by their formal characteristics, such as their cylindrical shafts or ornamented capitals, but equally by their material and the monolithic nature of that material. In order truly to revive the columnar architecture of Antiquity, architects had to resurrect the ancient column not just formally but also materially. While travertine was a workable, easily accessible substitute, it lacked the associative power inherent in ancient monoliths. Consequently, the process of formal imitatio, critical to the development of Renaissance architecture, came up against a limitation in Rome where awareness of the corporeal qualities of ancient columns remained strong. As the effort to resubstantiate ancient architecture intensified, it was only spoliated columns that could truly embody the authority of ancient columnar architecture.

THE GRANITE COLUMNS OF THE PALAZZO DELLA CANCELLERIA

Spoliated columns, as Georg Satzinger has outlined, were not completely absent from fifteenth-century Roman architecture. ²⁴ Nicholas V in the early 1450s, for instance, transported two, or possibly four, forty-foot monolithic columns from the Baths of Agrippa behind the Pantheon to St Peter's for use in a triumphal arch at the western end of the nave. At the end of the century, Innocent VIII and his successor Alexander VI matched this feat by employing a pair of giant granite monoliths in the triumphal arch at the Lateran basilica. ²⁵ However, unlike these exceptional cases, columnar spolia in fifteenth-century Rome was generally less monumental and often heterogeneous.

Because significantly reshaping hardened granite shafts with chisels was so difficult, builders often simply shortened them with saws, as at the Palazzo Vitelleschi (c. 1436–40), built in Tarquinia using spolia from Rome and Ostia. ²⁶ In other examples, these fragments were awkwardly retrofitted with travertine or marble necks, as in the cloister of S. Onofrio (c. 1434–44) and the courtyard of the Palazzo dei Conservatori (rebuilt c. 1451–53; Fig. 5). ²⁷ In the case of the Ospedale di S. Spirito, refounded by Pope Sixtus IV in 1474 and composed of two large courtyards, a number of irregularly shaped granite columns, interspersed among newly carved travertine shafts, were adapted by modifying the heights of their capitals (Fig. 6). ²⁸ In a city where most new courtyards and cloisters were being built exclusively of travertine, the spoliated columns of the Ospedale – the most used in any extant fifteenth-century Roman building – present themselves as a conscious architectural choice, possibly an attempt to appropriate Antiquity more directly. Yet without the ability to easily re-carve ancient granite shafts, its builders had to embrace the irregularity of the spolia and a consequent architectural aesthetic of variety.

Fig. 5. Rome, Palazzo dei Conservatori: courtyard

Fig. 6. Ospedale di S. Spirito: Chiostro degli Orfani

This was the paradox of using spoliated granite columns in the fifteenth century. While they spoke strongly of Antiquity, they were difficult to integrate into a unified all'antica composition. The builders of the Benediction Loggia of Pius II (begun in 1460) may have attempted to overcome this limitation by setting ancient granite columns in a composition modelled on the Colosseum and Tabularium. ²⁹ Yet, as this structure was destroyed in the early seventeenth century, it is impossible to know to what degree these granite shafts were successfully incorporated. It was only at the end of the century, with the construction of the Palazzo della Cancelleria, that such a feat would be unquestionably achieved and builders would unleash the full potential of spoliated granite columns through a process of re-carving.

Begun in 1489, the Palazzo della Cancelleria was built for Cardinal Raffaele Riario, the nephew of Pope Sixtus IV, who first came to Rome in 1471 and was subsequently, in 1483, given the commendam for the fourth-century church of S. Lorenzo in Damaso. ³⁰ Soon afterwards, he took up residence in the attached titular palace and, in 1486, began to restore the early-Christian church. ³¹ In that same year, according to Stefano Infessura's Diarium urbis Romae, Riario won 22,000 ducats from gambling with Franceschetto Cibo, the son of Pope Innocent VIII, and Cardinal Jean Balue. ³² With this tremendous sum of money, Riario pledged to rebuild his palace.

The new palace dwarfed its predecessor, enveloping not only the previous one, but also the adjacent church, part of the Via dei Leutari and the adjoining house of Francesco Maffei. ³³ Riario, to whom the first printed edition of Vitruvius (1486) was dedicated, was devoted to the revival of Antiquity. His new palace was to be the fullest expression of that revival, a fact noted by contemporary authors such as Raffaele Maffei and Paolo Cortesi. ³⁴ One of the primary means by which the Cancelleria did this was through direct citation rather than lose all'antica imitation. The courtyard capitals of the piano nobile, for example, directly emulate ancient capitals with rosettes from the Baths of Diocletian and the Basilica Aemilia. ³⁵ Likewise the piano nobile windows of the façade almost exactly replicate those of the Porta dei Borsari in Verona. This method of revival also extended to the travertine façade as a whole, which attempted to revive the ancient technique of ashlar construction, described by Vitruvius as opus isodomum, by imitating the drafted masonry seen on the Tomb of Cecilia Metella and other structures including a Roman wall under the Cancelleria itself. ³⁶ The builders of the façade also employed spoliated travertine. ³⁷ Thus, like the courtyard of the Palazzo S. Marco, the Cancelleria's façade went beyond simple formal citation by attempting to articulate an ancient material in an appropriately ancient manner. It was in the courtyard of the palace, however, that this mode of resubstantiation reached its zenith.

By 1496, attention at the Cancelleria worksite had turned away from the façade and towards the decoration of its interior, the destruction of the old church of S. Lorenzo in Damaso and the construction of an imposing new courtyard in its place. ³⁸ This courtyard is composed of a two-storey arcade with forty-four granite columns, plus eight granite L-shaped corner-piers – a staggering amount of spolia (Figs 7 and 8). ³⁹ On 23 November 1496, Riario made the first payments for the excavation and transportation of granite columns from terminj, the area of the Baths of Diocletian, to the Cancelleria construction yard. These columns, procured by Bernardino ingegnerj, are described in the payment records as ‘rochj di cholonne di granito per fare li pilastrj’ – columns of granite specifically for the creation of the corner-piers. ⁴⁰ Based on the width of the Cancelleria's lower corner-piers, these column shafts must have measured at least 1.4 m in diameter, making them similar in size to the monumental columns still in situ in the frigidarium of the Baths. ⁴¹ Additional records confirm that several large carts were purchased in 1497 for the transportation of these and other columns. ⁴²

Fig. 7. Rome, Palazzo della Cancelleria: plan (after Letarouilly)

Fig. 8. Rome, Palazzo della Cancelleria: courtyard

The choice to build with ancient granite columns at the Palazzo della Cancelleria was a momentous one, making it the first courtyard of the Roman Renaissance to be built completely of spoliated granite monoliths. This decision first required the builders to procure these columns, a laborious and expensive feat that necessitated excavation and the use of impressive lifting machines. ⁴³ But even once transported, hard granite shafts, often of varying proportions and dimensions, still presented the problem of integration. The Palazzo della Cancelleria changed this. Whereas spoliated granite columns had previously been used largely unaltered or simply shortened, the builders of the Cancelleria re-carved forty-four granite shafts into a matching set. ⁴⁴ They also transformed enormous cylindrical columns into eight L-shaped piers. This meant carving away half of these ancient granite shafts, completely altering their original form (Figs 9 and 10). To do all this, the builders looked specifically to Florence for tempered chisels that were hard enough to work ancient granite. Between 15 March 1497 and 7 November 1503, fourteen payments were recorded from the Cancelleria fabbrica to a blacksmith from Tuscany named ‘maestro Bernardino’. ⁴⁵ The first three of these documents record the acquisition of nineteen chisels (scharpelli) specifically for the carving of the granite columns (le cholonne di granito), while the majority of the later transactions concern the mending, re-forging and re-tempering of these chisels. ⁴⁶

Fig. 9. Rome, Palazzo della Cancelleria: north-west corner-pier of courtyard's ground storey

Fig. 10. Diagram illustrating how the L-shaped corner-piers of the ground storey were re-carved from ancient granite columns (after Bentivoglio)

It is unknown precisely why the fabbrica sought chisels from Florence, but, since all other tools were acquired from local Roman blacksmiths, the obvious answer is that the necessary tempered chisels were not available in Rome. Suzanne Butters has noted that Florentine artists and architects, such as Alberti, Verrocchio and Giuliano da Sangallo, were already experimenting with tempering in the fifteenth century, and some, such as Donatello, may have had experience of carving granite. ⁴⁷ Florence, therefore, may have been the closest city where tempered chisels of sufficient hardness were being produced. Since there is no evidence of ancient granite columns being extensively re-carved in Rome before 1497, it is likely the requisite building technology simply did not exist there before the building of the Cancelleria. The importation of these chisels thus represents a technological shift that had a direct impact on architectural production.

The innate hardness of granite alone made the re-carving of granite columns a significant act. In the Renaissance, hardness along with colour defined stones and was the means by which Vasari and others catalogued and valued them. The elemental hardness of granite thus imbued it with intrinsic value in a culture that appreciated this aspect of materials. Fioravante Martinelli, for example, wrote in the seventeenth century that the granite columns of Old St Peter's should be venerated because their ‘material has something of the eternal about it’. ⁴⁸ This hardness also imparted supposedly magical properties to the stone. As the humanist Angelo Decembrio wrote in the 1450s of the granite Vatican obelisk:

Even though people see the stone [granite] resisting iron chisels, not only in colour but also in its substance, and sparks bouncing off it, they still cut off little rinds, which they repeatedly smell and weigh in their hands, and finally they babble about how the work was carried out not by human power but by necromancy or magical arts. ⁴⁹

The immutability of granite in this way gave it meaning. The lost ability to carve granite columns thus represented much more than just the superiority of ancient technology: the material itself and its physical permanence embodied Antiquity's mysterious omnipotence.

The ability to reshape these granite columns would have been understood by contemporaries as equalling the achievements of the ancients. To those who still believed the impenetrable material held magical power, a belief that must have been heighted by its association with ancient Egyptian obelisks, transforming these relics must have been all the more extraordinary. Like transporting ancient granite monoliths, reworking these columns with tempered chisels was itself an act of revival. This was a laborious process in which granite was slowly chipped away with a pointed chisel, before being shaped with a toothed chisel and eventually brought to a polish with the use of emery. ⁵⁰ Contemporary viewers understood the difficulty of this undertaking. Master Gregory, in his early thirteenth-century Mirabilia urbis Romae, for example, wrote that a local cardinal claimed a single granite column from the Baths of Diocletian ‘could scarcely have been cut, polished and finished by a hundred men in the space of a year’. ⁵¹ It was the physical process of carving granite and knowledge of that process, as much as the end product, that held value. ⁵²

It was through the use of tempered chisels that the builders of the Cancelleria were able to unleash the potential of these ancient architectural remnants – specifically, re-carving transformed granite columns of varying sizes into a matching set that could be seamlessly integrated in the palace's two-storey courtyard. But, just as importantly, tempered chisels enabled workmen to make broken ancient columns whole again. This process breathed new life into ancient columnar fragments that had previously stood only for the demise of Antiquity and the passage of time. No longer did they signify ancient ruin, but once again they evoked ancient splendour. These courtyard columns, which remained identifiably ancient by virtue of their material, were thus proof that Antiquity had been literally renewed, revived and physically reborn. Spoliation in this way was not destructive but regenerative.

The L-shaped corner-piers of the Cancelleria courtyard further exemplify this mode of revival. Carved from several large columns, most likely fragments, from the Baths of Diocletian (and possibly elsewhere), the transformation of round shafts into angular piers is curious as this type of pier has little ancient precedent. ⁵³ Yet in the late fifteenth century, based partly on Vitruvius's suggestion that corner-supports should be wider to bear the thrust of arches, the L-shaped pier became a distinctly ancient element used in Roman peristyles, as illustrated by Francesco di Giorgio in the first version of his architectural treatise and Fra Giocondo in his 1511 edition of Vitruvius (Fig. 11). ⁵⁴ Architects at the same time also came to believe ancient Romans used this type of pier in the courtyard porticos (xysti) of imperial baths, as can be seen in contemporary reconstructions (Fig. 12). ⁵⁵ Thus, the builders of the Cancelleria, by re-carving ancient cylindrical columns into L-shaped piers, were in part attempting to recreate an ancient peristyle. But more than that, they were transforming columns spoliated from the Baths of Diocletian into granite L-shaped piers of the kind they believed once adorned the very same complex. To make sure the reference was clear, they topped the courtyard columns with capitals derived from those also found in this same structure. The corner-piers could have easily been carved from travertine, as seen in contemporary palaces and cloisters, but a conscious choice was made at the Cancelleria to use granite, and thus go beyond a fifteenth-century mode of imitatio to resubstantiate ancient Roman architecture. Architects and patrons wanted these new architectural elements not just to reference Antiquity, but to be ancient both formally and materially. Since L-shaped piers no longer existed, they had to be recreated from the very ancient columns that they once stood beside.

Fig. 11. Plan of a ‘modest house’ according to Fra Giocondo (M. Vitruvius, Venice, 1511, fol. 63 r)

Fig. 12. Anonymous (late fifteenth century), Baths of Diocletian (Florence, Uffizi, Gabinetto Disegni e Stampe, 1863 Ar)

The Cancelleria courtyard thus represents a paradigm shift in Roman Renaissance architecture. Technologically, the importation of tempered chisels enabled builders once again to carve hard ancient granite, liberating the stone from its previous limitations and allowing architects to embrace it as the columnar material of choice. Early sixteenth-century Roman architecture has traditionally been understood as the product of a desire to replicate more faithfully, authentically and archeologically the architecture of Antiquity through the study of Vitruvius and the measured drawing of ruins. Yet with the increased interest in the direct appropriation of Antiquity also came issues of materiality. Just as Baldassare Peruzzi, in the ceiling of the Jerusalem Chapel at S. Croce in Gerusalemme (completed by 1509), attempted to revive the art of mosaic in an effort to imitate ancient art in an ancient medium, architects beginning with the Cancelleria utilised ancient granite columns to join ancient form and material and signify the building's ancient authenticity. ⁵⁶ As the desire to resubstantiate ancient architecture grew stronger, it became necessary to employ ancient granite monoliths rather than simply replicating their formal characteristics. It was only spolia that could embody the materiality of ancient columnar architecture – only ancient columns could stand for ancient columns in this new architectural mode.

BRAMANTE AND SPOLIATED GRANITE COLUMNS

Donato Bramante, credited by Andrea Palladio with bringing to light the ‘good and beautiful architecture of the ancients’, arrived in Rome at the end of 1499. ⁵⁷ According to Vasari, he almost immediately began studying ‘all the ancient buildings’, and was consulted on the Palazzo della Cancelleria, which was still under construction. ⁵⁸ Regardless of the validity of these remarks, the architect undoubtedly gained an early familiarity with the city's ancient ruins and its most notable new building. As is evident in his Roman work, including the famous Tempietto of S. Pietro in Montorio (Fig. 13), Bramante fully embraced the architecture of Antiquity, and like the builders of the Cancelleria, he sought to resubstantiate it through the exploitation of spoliated granite columns.

Fig. 13. Rome, Tempietto di S. Pietro in Montorio

Begun as early as 1502, Bramante's Tempietto is a round peripteral temple, composed of sixteen spoliated granite columns surmounted by a Doric frieze, drum and dome, built to mark the site of St Peter's martyrdom. ⁵⁹ Its formal characteristics have led historians to trumpet the building as the advent of a new ‘classical’ Renaissance architecture which, according to Wolfgang Lotz, came closer to the ‘essential nature of ancient architecture’ than anything before. ⁶⁰ It is difficult to deny that the Tempietto derived much of its ancient authority from its formal qualities; yet the granite columns themselves would also have spoken strongly of Antiquity to contemporaries. Even Palladio, in his short three-sentence description of the structure in the Quattro libri, mentions that the columns are granite. ⁶¹ While it is unknown if their relatively slender shafts, measuring 3.1 m in height, were purposefully re-carved, the use of three different types of granite suggests this is likely. ⁶² What is clear is that the proportions of the building as a whole correspond to those of the columns. ⁶³ The granite shafts of the Tempietto were thus fundamental to its design. While they visually stand apart from the rest of the structure, much of which is made of travertine, they are fully integrated into its classical composition.

The columns, as identifiably ancient elements, may have also been understood by contemporaries, like the form of the building as a whole, as pagan features re-consecrated to serve a new Christian function. ⁶⁴ Their spoliation and architectural subjugation could thus serve to demonstrate Christianity's continual triumph over paganism. They also link the Tempietto to the granite column-lined, circular churches of S. Costanza and S. Stefano Rotondo, both of which were believed in the Renaissance to be re-consecrated ancient temples. ⁶⁵ In this way the Tempietto's spoliated columns were critical to the building's ancient aura. As much as the building's form, they linked the Tempietto physically back to the time of St Peter's crucifixion and the re-sanctified architecture of Antiquity.

Bramante's use of ancient granite columns continued in his subsequent work for Pope Julius II. They adorn, for example, the serliane of his S. Maria del Popolo tribune (c. 1506), the Sala Regia in the Vatican Palace (c. 1507) and the spiral staircase of the Cortile del Belvedere (begun around 1507). This final structure, which was part of an ambitious series of projects envisioned by the pope and Bramante for the Vatican, has an outer ramp that makes four revolutions around a central void (Figs 14 and 15). ⁶⁶ As the ramp spirals upward, the columns that support its inner edge transform from short stocky Tuscan to slightly more ornate slender Doric, to slimmer voluted Ionic and finally to an even more attenuated and decorated Corinthian/Composite. The shafts of the first thirty-one columns are granite, while the originally last, uppermost column is of grey marble. ⁶⁷

Fig. 14. Rome, Belvedere staircase: cross-section (after Letarouilly)

Fig. 15. Rome, Belvedere staircase

What is astonishing is that each granite shaft reduces in diameter by less than a centimetre from its predecessor, diminishing from 50 cm at the bottom to 31 cm at the top. ⁶⁸ While numerous scholars have written extensively on the progression of the orders and the proportions of the columns, they have largely ignored the exceptional nature of this continuous diminution. ⁶⁹ The amount of work it took to reshape thirty-one granite columns to such stringent dimensional requirements must have been extraordinary. With all of the ambitious construction projects of Julius II, including the construction of the Cortile del Belvedere and the rebuilding of St Peter's, it is all the more remarkable that so much effort was dedicated to something few people would see, since the sole purpose of the staircase was to provide access for the most privileged to the papal collection of antiquities above.

The spiral staircase plays to this elite audience who viewed staircases as important sites of courtly display. It is a work of bravura, designed to envelop the visitor in an architectural progression marked by pieces of Antiquity in the form of ancient granite columns on the left and ancient statues set in niches on the right, culminating in the famous sculpture court above. In this case, the ancient proportions of the spoliated columns were expendable; the whole concept of columnar proportion was secondary. The emphasis of the spiral staircase was instead on the hard ancient granite shafts and their seemingly miraculous transformation into a series of gradually diminishing classical columns as one ascended. In this way, Bramante made it manifestly clear that these columns had been re-carved. Yet instead of alluding to the slow, difficult process required to reshape them, in an almost cinematic fashion, the staircase makes this performance look effortless, like an architectural embodiment of sprezzatura. Such transformations and subversions, although largely overlooked today, would have resonated with the stairway's elite viewing audience, who appreciated the nature of materials and were cognisant about their standard contemporary use. The spiralling transformation of one of the hardest of ancient stones would thus have been understood as a Herculean achievement worthy of the ancients. It also made the spiral staircase an integral component of the antique programme of the Belvedere as a whole, while giving almost literal credence to Sebastiano Serlio's statement that Bramante had ‘brought back to life the architecture of Antiquity that had lain buried’. ⁷⁰

THE TRIUMPH OF GRANITE

A final testament to the power and popularity of granite before the Sack of Rome in 1527 is a series of palaces built by a variety of patrons and architects. These buildings – Palazzo Lante-Medici, Palazzo Cardelli (now Palazzo di Firenze), Palazzo Sangallo in via Giulia, Palazzo Regis ai Baullari, Palazzo Ossoli, Palazzo della Valle and Palazzo Farnese – are a diverse group varying in size as well as arrangement, yet they all exploit spoliated granite columns. ⁷¹ Together they confirm the tremendous architectural shift that occurred in the city of Rome in the wake of the Palazzo della Cancelleria. Granite had once again become a critical component of Roman architecture. Through the use of ancient monolithic granite columns, each of these palaces attempted to insert itself into the forefront of the city's architectural development.

Some of these buildings also kept pace with the current architectural climate by providing their smaller courtyards with the same kinds of features found in the most grandiose palace to date. For example, when Andrea della Valle enlarged his family palace between 1507 and 1517, he built a new courtyard on the model of Palazzo della Cancelleria. While the L-shaped corner piers of this structure were made of travertine, he attempted to equal the Cancelleria by adorning its courtyard with spoliated marble and granite column shafts, topped with marble capitals, and accompanied by roundels made of the ancient stones porphyry, verde antico and africano, and ancient statuary set in niches. Spoliated granite, like ancient sculpture, was also an indicator of wealth and social status, as well as a commodity to be bought, sold and displayed. The papal banker Agostino Chigi, for example, spent the extravagant sum of 300 scudi on a monolithic granite step for his new chapel in S. Maria del Popolo (begun 1513). ⁷² Even small residences, such as the Casa dei Fabi at the Porticus of Octavia (Fig. 16), employed granite columns, presumably to demonstrate the family's social standing and ancient heritage. ⁷³

Fig. 16. Rome, Casa dei Fabi (via Portico d'Ottavia, 13): courtyard

Arguably the greatest example of this phenomenon is the Palazzo Farnese. Cardinal Alessandro Farnese, who obtained an earlier cardinal's palace in 1495, began to rebuild this residence in the mid-1510s. Under his aegis, Antonio da Sangallo the Younger designed a monumental palace with an entry vestibule flanked with twelve alternating red and grey granite columns that were in place by the early 1520s (Fig. 17). ⁷⁴ In its form, this space emulates the column-lined vestibulum of an ancient house, as described by Vitruvius and illustrated by Fra Giocondo in 1511 (Fig. 11). Yet materially, the architect and patron chose granite columns to support the classically-inspired barrel vault. ⁷⁵ Like the Belvedere staircase, the visitor would thus enter into a space defined by ancient granite columns and statuary set in niches that established the tone of the classically inspired whole. It is not accidental that the Florentine Fra Mariano specifically mentioned these ‘beautiful columns’ in his 1518 description of ancient and modern Rome. ⁷⁶ For sixteenth-century viewers entering the vestibule, it was the spoliated granite columns themselves, coupled with the formal language of classicism, that gave the impression that Antiquity had been revived.

Fig. 17. Rome, Palazzo Farnese: vestibule

After the Sack of Rome in 1527, the use of ancient granite columns in new construction continued, but their popularity waned. Nonetheless, as the century came to a close, granite columns remained potent bearers of meaning, adorning the courtyard of Rome's last great Renaissance palace – the Palazzo Borghese. Built between 1572 and 1612, the palace's courtyard is lined with ninety-six paired columns, almost all of which are granite (Fig. 18). ⁷⁷ Not since the Palazzo della Cancelleria had Rome seen a structure with so many spoliated granite shafts. The courtyard of the Palazzo Borghese is thus a final witness to the enduring power of granite in the city of Rome through end of the sixteenth century.

Fig. 18. Rome, Palazzo Borghese: courtyard

Yet by the twentieth century this power had largely been obscured. As spoliation died out, mechanical technology emerged and a worldwide system of quarrying was established, knowledge of the means by which ancient granite columns were procured and transformed in Renaissance Rome was lost. With this disconnect from process, much of the original meaning of these columns slowly disappeared. At the same time, the material itself was progressively hidden under the universal grey patina of pollution. This problem was only compounded by the proliferation of monochrome prints and photographs of these buildings. Yet by returning to the monuments themselves and examining them in terms of their materiality, it is possible see how the architecture of revival was directly tied to the physical appropriation of Antiquity in Rome. Through the use and transformation of spolia, specifically ancient granite columns, builders and patrons attempted to create an architecture that not only recalled Antiquity, but resubstantiated it, literally making it whole again. In this way, it authenticated the idea that the architecture of ancient Rome had actually been brought back to life and renewed. Spoliated granite columns were a physical proof of this rebirth.