cathedral nato

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Construction and Building Materials 17 (2003) 521–532 0950-0618/03/$ - see front matter 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0950-0618(03)00051-5 Building the Cathedral of Noto; earthquakes, reconstruction and building practice in 18th-century Sicily Stephen Tobriner University of California at Berkeley, Berkeley, CA, USA Received 23 May 2001; accepted 18 August 2003 Abstract The collapse of the nave and dome of the Cathedral of Noto, S. Nicolo, in a rainstorm in 1996 brought to light 18th century ` construction errors unique to this building. S. Nicolo is the most prominent church in the city of Noto, a rich Baroque center in ` southeastern Sicily completely reconstructed after an earthquake in 1693. During the course of its construction and reconstruction between 1696 and 1950, S. Nicolo was plagued by multiple earthquake failures and construction errors. This paper attempts to ` assemble the unwritten construction history of the church for the first time in English, and to address the question of how architects, engineers and builders responded to the problem of creating a seismically resistant building. 2003 Elsevier Ltd. All rights reserved. Keywords: Cathedral of Noto; Sicily; Earthquakes; Construction failure The Cathedral of Noto (Fig. 1) still dominates its city with grace and majesty despite its gutted interior and broken dome. The collapse of S. Nicolo on 13 March ` 1996 was just the latest misfortune in a long succession w1x. From shortly after the inception of city on its present site until the late 19th century, collapses and closures plagued the church. S. Nicolo collapsed at least ` three times before, and on different occasions in the 18th and the 19th century, knowledgeable critics alleged it was incorrectly and incompetently built. During the many occasions the building was closed for repairs, other churches substituted as the city’s Chiesa Madre (Mother Church) just as the ex-Jesuit church of S. Carlo does today. Then, as now, the process of reconstruction was agonizingly slow. Then, as now, a new team of architects and engineers had to cope with the sometimes misguided decisions of earlier architects, engineers, capomastri and mastri. Earthquakes have played a crucial role in the long construction history of S. Nicolo. The foundations of ` the original Chiesa Madre of S. Nicolo can still be seen ` 7 km northwest of the present city among the ruins of old Noto (Noto Antica), destroyed in the earthquake of 1693. The Baroque city of Noto and its Chiesa Madre E-mail address: [email protected] (S. Tobriner). of S. Nicolo are products of a massive earthquake ` reconstruction effort that continued into the late 18th century. When earthquakes rumbled through the new city of Noto in 1727, 1780, 1818 and 1848, each damaged or collapsed S. Nicolo. The last earthquake to ` strike the city in 1990 opened cracks in the church, which directly contributed to its failure in the rainstorm of 1996 w2x. Since antiseismic engineering was known in 18th-century Sicily and even in Noto, it is fair to ask whether an attitude toward earthquakes and architecture can be deduced from the structure itself. After repeated failures, is there any indication that an architect, engineer or craftsman working on the structure especially consid- ered the danger of earthquakes? The temporary church of S. Nicolo built in 1693 was ` certainly influenced by the fear of earthquakes. Because citizens feared the return of the deadly earthquakes that leveled not only Noto but more than 40 cities in southeastern Sicily, they built small low structures throughout the 1690s w3x. Wood for the temporary buildings, or baracche of Noto, was imported from Calabria and used sparingly. The baracca of S. Nicolo, ` like others in the city, was modest. But within a decade, all over Noto, the temporary buildings were being replaced by larger ones in stone. Among these permanent

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Page 1: Cathedral Nato

Construction and Building Materials 17(2003) 521–532

0950-0618/03/$ - see front matter� 2003 Elsevier Ltd. All rights reserved.doi:10.1016/S0950-0618(03)00051-5

Building the Cathedral of Noto; earthquakes, reconstruction and buildingpractice in 18th-century Sicily

Stephen Tobriner

University of California at Berkeley, Berkeley, CA, USA

Received 23 May 2001; accepted 18 August 2003

Abstract

The collapse of the nave and dome of the Cathedral of Noto, S. Nicolo, in a rainstorm in 1996 brought to light 18th century`construction errors unique to this building. S. Nicolo is the most prominent church in the city of Noto, a rich Baroque center in`southeastern Sicily completely reconstructed after an earthquake in 1693. During the course of its construction and reconstructionbetween 1696 and 1950, S. Nicolo was plagued by multiple earthquake failures and construction errors. This paper attempts to`assemble the unwritten construction history of the church for the first time in English, and to address the question of howarchitects, engineers and builders responded to the problem of creating a seismically resistant building.� 2003 Elsevier Ltd. All rights reserved.

Keywords: Cathedral of Noto; Sicily; Earthquakes; Construction failure

The Cathedral of Noto(Fig. 1) still dominates its citywith grace and majesty despite its gutted interior andbroken dome. The collapse of S. Nicolo on 13 March`1996 was just the latest misfortune in a long successionw1x. From shortly after the inception of city on itspresent site until the late 19th century, collapses andclosures plagued the church. S. Nicolo collapsed at least`three times before, and on different occasions in the18th and the 19th century, knowledgeable critics allegedit was incorrectly and incompetently built. During themany occasions the building was closed for repairs,other churches substituted as the city’s Chiesa Madre(Mother Church) just as the ex-Jesuit church of S. Carlodoes today. Then, as now, the process of reconstructionwas agonizingly slow. Then, as now, a new team ofarchitects and engineers had to cope with the sometimesmisguided decisions of earlier architects, engineers,capomastri andmastri.Earthquakes have played a crucial role in the long

construction history of S. Nicolo. The foundations of`the original Chiesa Madre of S. Nicolo can still be seen`7 km northwest of the present city among the ruins ofold Noto (Noto Antica), destroyed in the earthquake of1693. The Baroque city of Noto and its Chiesa Madre

E-mail address: [email protected](S. Tobriner).

of S. Nicolo are products of a massive earthquake`reconstruction effort that continued into the late 18thcentury. When earthquakes rumbled through the newcity of Noto in 1727, 1780, 1818 and 1848, eachdamaged or collapsed S. Nicolo. The last earthquake to`strike the city in 1990 opened cracks in the church,which directly contributed to its failure in the rainstormof 1996 w2x. Since antiseismic engineering was knownin 18th-century Sicily and even in Noto, it is fair to askwhether an attitude toward earthquakes and architecturecan be deduced from the structure itself. After repeatedfailures, is there any indication that an architect, engineeror craftsman working on the structure especially consid-ered the danger of earthquakes?The temporary church of S. Nicolo built in 1693 was`

certainly influenced by the fear of earthquakes. Becausecitizens feared the return of the deadly earthquakes thatleveled not only Noto but more than 40 cities insoutheastern Sicily, they built small low structuresthroughout the 1690sw3x. Wood for the temporarybuildings, or baracche of Noto, was imported fromCalabria and used sparingly. Thebaracca of S. Nicolo,`like others in the city, was modest. But within a decade,all over Noto, the temporary buildings were beingreplaced by larger ones in stone. Among these permanent

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Fig. 1. S. Nicolo. Facade overlooking the main piazza of Noto with a fragment of the dome still standing in 1998(photo: author).`

buildings was S. Nicolo, begun in 1696. Like other`buildings in the new Noto, S. Nicolo was a patchwork`of newly quarried and previously cut stonework. Asstonemasons established quarries on the slopes of thenew site of Noto, they sent mule train after mule trainto Noto Antica to excavate stone from the ruins. Themarble portal of the main doorway of S. Nicolo, lying`in ruins in Noto Antica, was transported to the new cityin 1696 and incorporated in the new facade. In 1718the insignia of the city found in Noto Antica wassolemnly affixed to the facade of the new Chiesa Madreclearly underscoring the transfer of the city.In the midst of reconstruction a major earthquake

struck Noto in 1727, badly damaging the new stone S.Nicolo for the first timew4x. So badly damaged was the`marble main portal in the earthquake of 1727 that itwas at risk of total ruin. This decorative feature and thestone around it, which had previously collapsed withthe old church in 1693, nearly failed after it was installedin the new. The interior of the church must have beenat risk as well because authorities removed the preciousArch of S. Corrado(the patron saint of Noto) andinstalled it for safe keeping in the church of S. Domen-ico. The 1727 earthquake not only damaged S. Nicolo`but the facade of the church of S. Francesco broke apart,the vault of S. Agata fell, the cross of the church of SS.Trinita tumbled off, S. Maria di Gesu was damaged and` `a portion of the facade of the Jesuit seminary facing thepresent Piazza XVI Maggio collapsedw5–7x.The 1727 earthquake should have proven to the

people of Noto that seismic events recurred and that

they were extremely dangerous to masonry structures.Yet no evidence of antiseismic construction techniquesappears in the first church of S. Nicolo, badly damaged`in the earthquake of 1727, even though this first churchwas built within memory of the great earthquake of1693. Just the year before, in 1726, a major earthquakedestroyed scores of buildings in Sicily’s capital city ofPalermo, only a few days ride from Noto. Palermo hadinitiated some surprisingly avant-garde antiseismic con-struction methodsw8x. For example, after the 1726Palermo earthquake we know that antiseismic solutionsfor domes made of stucco and wood instead of stonewere discussed and implemented. Strengthening of dam-aged structures through the copious use of iron wasintroduced. Even a law prohibiting the use of heavybalconies was promulgated. The connection betweenpoor alluvial soil and building damage was being con-sidered, as Domenico Campolo’s map of Palermodemonstrates.What effect did the lessons of the Palermo earthquake

of 1726 and the earthquake of 1727 have on reconstruc-tion in Noto? An aristocrat writing Noto’s early historystates that after the earthquake ‘the walls of convents,palaces and churches were in such poor condition, sofull of fissures, that they had to be repaired either withbuttresses or iron chains.’ Rosario Gagliardi, the mostfamous architect working in 18th-century Noto, musthave known about how to build antiseismically. Forexample, Gagliardi was employed as the architect of thenew church of S. Maria la Rotonda in 1730 in whichthe walls were strengthened with iron rodsw9x. Twenty

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Fig. 2. S. Nicolo. Plan illustrating successive building campaigns(drawing: Emanuele Fidone).`

years later in 1750 in an assessment of the church of S.Michele in the Sicilian town of Scicli, he proposed twosolutions to roofing in relationship to earthquakesw10x.He advised that light vaults of wood and cane andplaster would resist earthquakes more effectively thanstone arches. Gagliardi’s discussion of vaults in Scicliproves he was cognizant of seismic hazards and under-stood antiseismic strategies. Yet no seismic strengthen-ing is recorded at S. Nicolo. While workers seem to`have been repairing thepietra d’intaglio (ashlar mason-ry) of the ‘arches, pilasters, and windows’, Gagliardiwas employed to take down and to remount the bells ofthe church. It seems that Gagliardi was adding a singlebelfry to the facade, perhaps a miniature or full-scaletower facade. What is not described are the antiseismiciron rods or chains he used in S. Maria la Rotonda.Instead, the upper part of the facade, probably ruined inthe earthquake, is remade. It is difficult to judge thiswork in relation to seismic safety.Between October 8, 1745 and August 21, 1746, for

reasons still unclear, the campaign to finish the firstchurch was abandoned and an entirely new churchbegun. Perhaps the earthquake of 1727 had dealt thefirst church a fatal blow, the extent of which expertsonly realized over time. It is possible that the initialdamage caused further failures much later just as the

damage from the 1990 earthquake contributed to thefailure of S. Nicolo in 1996. Social and aesthetic reasons`could also account for the abandoning of the 1696design. Perhaps the first church, still incomplete, wasinsufficiently large or grand in relation to new motherchurches being erected in other cities of southeasternSicily. The new second church begun in the 1740s wasdesigned to encapsulate the nave of the first church(Fig. 2). Documents record that stone was delivered tothe site as early as 1746. The shipments of stone werepresumably for the new walls for the apse and chapelsbeing built at the northern end of the church, whichcould be built while the facade and nave of the firstchurch remained undisturbed.Authorities called in Gagliardi in 1753 to render an

expert’s opinion as to the condition of the first church.The question was whether to reutilize the nave andfacade of the first church or finance new construction.Gagliardi strongly condemns the construction and aes-thetics of the entire first church in order to force churchauthorities to finance a new building. Gagliardi’s con-demnation is extreme: ‘internally and externally I declarethe building to be false to architecture without thepossibility of being able to be brought to any approxi-mation of proportion or architectural perfection. Second,you can’t vault it because the walls are very weak and

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Fig. 3. S. Nicolo. Detail of lateral elevation(photo: author).`

full of holes«In my view the church should be demol-ished and so the new church, which one can see isalready underway, and rises with a fine and regularsense of architecture can be built.’ Gagliardi’s condem-nation of the structure and the architectural design ofthe first church is a legal document and must have beentaken extremely seriously. That he did not exclude hisown work on the facade is surprising, since his condem-nation could be legally binding, inferring that the archi-tects who had directed the works(himself included!)would have been financially responsible for the short-comings of the building. A second document of October1, 1753 complained that the walls were improperlyconstructed of ‘pietra molle’ (soft stones).After initial reluctance the church officials endorsed

the new second church. From 1764 to 1769 work beganon the chapel of S. Corrado, the chapel of the SS.Sacramento, the left campanile and the right lateralelevation of the second church(Fig. 2). The lateral rightwall (Fig. 3) was laid outside the perimeter of the naveof the first church, which was still intact. Both the rightand left lateral elevations with their dynamic rhythms,expressive decorative features and quality of surface anddepth are in the style of Rosario Gagliardi. Between1769 and 1776 the old church in the interior of the newwalls was demolished, and the new interior with piersto support the clerestory, the facade and dome wasconstructed.Although his name is never mentioned in the docu-

ments, the author of the plan and original elevation forthe second church of S. Nicolo is probably Rosario`

Gagliardi. The plan of the church is very close to anumber of variants of a basilica plan attributed toGagliardi as well as to other buildings he designed likeSS. Crocifisso in Noto. Only in 1767 is the ‘architetto’named, and he is Gagliardi’s associate, Vincenzo Sinatraw11x. Before Gagliardi died in 1762 Sinatra had estab-lished a close professional relationship with him, whichwas further strengthened when Sinatra married Gagliar-di’s niece. Working for Vincenzo Sinatra as hiscapo-mastro was Giuseppe Sinatra, Vincenzo’s son by aprevious marriage. By the time construction of thefacade had begun, Gagliardi’s full Baroque style hadwaned in popularity and Sinatra toned down the facade,as his patrons, the aristocrats of Noto, would havewished. The second church was opened for services in1776.Several features of the second church of S. Nicolo`

could have been attempts to make it seismically resis-tant. The first possibility is that the lateral elevation ofGagliardi’s project called for a building with excessivemass and a low height to width ratio, which loweredthe center of gravity. The massive lateral walls and deepchapels of the nave(Fig. 4) might aid the stability ofS. Nicolo in an earthquake. The depth of the wall itself`and its continuity with minimal apertures, combinedwith the interior walls, which link it to the internal piers,provide resistance in two directions. Further, the but-tresses above the lateral facades help stabilize theclerestory walls(Fig. 7). The second possibility is thatGagliardi may have attempted to lessen mass bearingon walls. If the interior were vaulted in cane and plaster,

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Fig. 4. S. Nicolo. Interior as seen from remains of roof at crossing(photo: author).`

Fig. 5. S. Giorgio, Ragusa. Elevation. Rosario Gagliardi(Archives of S. Giorgio, Ragusa).

exerting negligible thrust on the clerestory walls, theseismic threat to the structure would have been lessened.Gagliardi designed domes in Noto like the one atop theJesuit church of S. Carlo, as ‘Lombard domes’, withframed timber roofs and interiors of wood, bamboo andstucco instead of heavy masonry. The interior of S.Chiara has an intricately designed light stucco andwooden vault. In his work throughout Noto there is alack of large domes, tower facades or high towers. An

acknowledgment of seismic problems might explain whyGagliardi’s church of S. Domenico is unusually squatand why he adopted the method of miniaturization inhis tower facade churches which reduced how far thelast story projected above the roof. Because S. Nicolo`was the Chiesa Madre, it required a dome. The kind ofdome favored by Gagliardi is illustrated in his designfor S. Giorgio in Ragusa Ibla of 1738(Fig. 5). Thisdome with its modest cupola, low drum and heavy walls

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Fig. 6. S. Nicolo. Plan illustrating discrepancy between buttresses and transverse arches(drawing: Emanuele Fidone).`

is extremely conservative. Unfortunately, like all domeswhether they be masonry or of steel, this one wouldhave been at risk in earthquakes.Several puzzling changes, perhaps related to earth-

quake damage, occurred in the nave during the construc-tion of this second church. The internal transverse archesare not aligned with the exterior buttresses(Figs. 6 and7). How can this strange inconsistency be explained?One could hypothesize the presence of a truss roof thatwas built in relation to the external buttresses, perhapsdesigned for a lower stone vault in a first campaign,around 1770. This solution was then changed to the onewe see today. They decided on a higher vault in caneand plaster with the transverse arches in stone, whichare off-axis in relation to the buttresses. The builderscould have decided to alter their original design foraesthetic or structural reasons. It is possible that thebuilding may have been damaged by the earthquakes of1666 and 1667, which struck Noto. It is also possiblethat cracks appeared in the piers of the building, causingbuilders to rethink the design for the clerestory, roof andvault. If this hypothetical change did occur, the dimin-ishing of the weight of the vaults could be seen as anantiseismic strategy, but the off-axis arches introducetorsion into the structure because of the irregularity ofthe load path.Only one remaining antiseismic feature was present,

if in a minimal way, in the church. In one document‘iron for the cinches around the small lanterns’ ismentioned. Iron ties are an effective way of strappingdomes and tying walls together, and this single document

is the only evidence we have that iron was being usedto reinforce any part of the structure. No iron ties orchains appear in the ruins of the building.The ruins of the second church of S. Nicolo(Figs. 4`

and 8) and the documents related to its construction arein accord: This was a masonry building built in thetradition of Noto w12x. Like other Noto buildings S.Nicolo is entirely stone, without a single brick. The`stones called out in the documents are the stones thatwere used in other buildingsw13x. Some are quarriedfrom the site of the city and others are brought fromquarries nearby. They include various grades of sand-stone and limestonew14x. The construction techniquesare similar to those described by Giovanni Biagio Amico(1684–1754) in his treatiseL’Architetto Prattico (1726y1750) and detailed by modern scholars of 18th-centurySicilian architecturew15x. Amico writes that among thevarious kinds of walls, ‘There is also another way ofmaking encased walls«in which the exterior is con-structed of squared stones and linked together with othersquared stones keyed at right angles, and filled withstones and earth, or mortar. In Sicily they use mostlyuncut and roughly cut stone, filling the remaining voidswith small stones and mortar with finely hammeredlime’ w16x. This stone-masonry technique, described byVitruvius, was well known in Antiquity. The ruins ofthe exterior walls of S. Nicolo clearly illustrate the use`of irregular stones placed in rough rows inside an outerring of cut stone,pietra d’intaglio. This technique wascommon throughout southeastern Sicily as a comparisonbetween S. Nicolo and the Monastero dei Benedettini`

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Fig. 7. S. Nicolo. Exterior buttresses(photo: author).`

of Catania demonstratesw17x. The ultimate stability ofthe mass of stones depends upon the strength of themortar and if all else fails on the ashlar masonry skinof the wall.In the last campaign to finish the nave of S. Nicolo,`

stonemasons made a major miscalculation in the con-struction of the nave piers, which nullified any attemptto make the building safe in earthquakes. The staticloads of the clerestory, side vaults, nave vaults and domeare all carried by the piers, so their construction isparticularly important. But in S. Nicolo the nave piers`are the weakest part of the entire building because ofone mistake, the use of round river stones in theirconstruction(Fig. 9). While river stones are excellentin compression, they are smooth and round making itdifficult for mortar to adhere to them. As architecturaltreatise writers uniformly advise, they must be brokenup if used in walls. To do otherwise is to build astructure that violates the rules of good architecturalpracticew18x. After the Calabrian earthquakes of 1783,authorities condemned the use of round river stones inwalls as being one of the causes for building failures in

earthquakesw19x. The Bourbon government of Naplesprohibited the use of uncut river stones in all newconstruction in Calabria.The mistake of using round river stones in the piers

is compounded by the use of poor rubble limestone andweak mortar and an even weaker external ashlar revet-ment w20,21x. The mortar in the piers is not particularlystrong and was not viscous enough to penetrate betweenthe rubble. As a result there are unfilled holes in thecores of the piers. The stones in the core are of poorquality as well. In fact, except for the river stones,Gagliardi’s description of the construction weakness ofthe first church, and his accompanying condemnation ofthe same year, fit the description of the construction ofthese piers and the stones of which they are composed.The exterior ‘pietra d’intaglio’ had the potential ofconfining the problems of the core. But only one thinwidth of cut stones was laid. Unlike designs advised byVitruvius, which were supposed to be made of chainsof stones, here there is but one width of poorly bondedstone. To make matters worse, the design of the piershad indentations for niches that induced the masons tolay stones that in some cases touched only at the corners.The miracle is that S. Nicolo stood as long as it did.`How can the poor construction of the piers be

explained? It should be noted that the piers, nave roofand dome were the last part of the building campaign,coinciding with the demolition of the old church. Theupper parts of the church are better crafted with materialsuperior to the lower. The demolition of the old churchwould have produced a great deal of material that wouldhave had to be carted away. Gagliardi’s condemnationof the first church was long forgotten. Perhaps materialfrom the first church was reused in the piers to simplyuse it up. The river stones, too, were probably on thesite. Perhaps there had been an overrun and these stoneswere extras. So to use up unwanted material the basesof the piers were begun with river stones and softlimestones. There also could have been unsupervisedfilling of the carefully cut exterior perimeters of thepiers. Master masons set the cut stonepietra d’intagliowhile day workers may have been responsible for fillingthe interiors. Hence the mistake.Another possibility exists, which is linked to the

reluctance of the aristocrats to fund the project and theanxiety of the populace regarding their unfinished Chie-sa Madre. After the initial ardor to complete the building,enthusiasm waned. In the 1740s and 1750s aristocratsappear to have been reluctant to fund the project. Insteadthey concentrated on their own churches and chapels.But by 1770 the funding outlook brightened. A docu-ment of 1770 enumerates an aristocratic bequest offunds to the Chiesa Madre that so inspired the populacethat they donated not only their own money but theirown labor, motivated by ‘un Santo Zelo’. What effectdid this ‘zeal’ combined with faith and impatience have

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Fig. 8. S. Nicolo. Interior with broken piers on left(photo: author).`

on the construction of the church? Is it possible that thecitizens of Noto were moved, like the aristocrats andcommoners of the Miracle of the Carts in MedievalChartres, to carry stones to the construction site of theChiesa Madre? Could these stones have come from theAsinaro River that flows near the site of Noto? Facedwith the pious donation of mounds of inappropriatematerial, and the further donation of free unskilled labor,perhaps thecapomastri headed by Giuseppe Sinatramade disastrous misjudgments. Yet another possibilityis that seeing the poor quality of the rubble limestoneavailable for the filling of the piers thecapmastrodecided that stronger limestone, even in the shape ofsmooth river stones, was better than nothing. Under-standing the problem he interspersed the river stoneswith the other fill in the piers.The piers may have begun to show signs of weakness

during construction. The vertical cracks discovered inthe piers by Luigia Binda and her group of researchersindicate that they were spreading and buckling undervertical gravity loads at least as early as the re-plasteringof the church around 1950 and most likely beforew22x.Could the cracks have alarmed thecapomastri sufficient-ly for them to attempt to diminish the load by lighteningthe roof? Could this explain the puzzling change in thevault design? We will never know.S. Nicolo’s construction history is complicated still`

further by the failure and reconstruction of its dome.While a detailed history of the domes of S. Nicolo is`not germane to this essay, an assessment of their possibleantiseismic qualities is. The dome of the second church,

the first dome, was badly damaged in an earthquake onJune 5, 1780. The dome collapsed and the remains ofboth the dome and the apse were demolished by lateJune. In 1789 the French traveler Leon Dufourny´describes work under way to build a second dome.According to Dufourny, the architect Stefano Ittar wasin charge of the works. Dufourny explains that Ittar wasdiminishing the dimensions of the windows of thecrossing and reshaping them as ovals in an attempt toprovide better support for the dome. Dufourny is dubiousthat this strategy is sufficient to correct the problem.Since Ittar is never mentioned in the documents, it ispossible he left the project, which was then executed byBernardo Labisi, the son of Paolo Labisi, who appearsin the cantiere of S. Nicolo as an architect in 1809 and`as an engineer in 1809 and 1813. By 1816 windowswere installed and by 1817 the dome was plastered. In1818 another earthquake damaged the new second dome.It was evaluated for possible repairs in 1839, only to beshaken to ruins in 1848. The third dome was begun byLuigi Cassone in 1857 and completed in 1861.Unfortunately, information about the first two domes

is extremely limited, and even the design process of thethird is unclear. Still the question can be posed whetherthere is any evidence of antiseismic construction fea-tures. In other words are there any special design featuresor reinforcement strategies particular to antiseismicdesign? Several possibilities emerge. The first involvesthe partial filling of the nave windows at the crossingbefore the installation of the second dome that Dufournyascribes to Stefano Ittar(Fig. 10). This method of

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Fig. 9. S. Nicolo. A broken pier illustrating river stones in core and`cut stone facing(photo: author).

Fig. 10. S. Nicolo. Oval window and buttresses at crossing. In the late`18th century the original aperture was diminished and a smaller ovalwindow inserted to add strength to the crossing(photo: author).

strengthening a bearing wall under a dome was usedbefore in the famous church of Hagia Sophia in Istanbul.After the second dome of Hagia Sophia partially col-lapsed in an earthquake in 984AD, several windowswere closed to consolidate and strengthen the domew23x. Ittar may have also designed the buttresses of thecrossing below the dome, which are built of inclinedcut stone to effectively counter the thrust of the weightof the drum. The beautiful stonework thoughtfully laidto counter the lateral thrust contrasts markedly with thework in the rest of the building. Another example ofantiseismic considerations was the unsuccessful attemptby Cassone to limit the weight of the third dome byusing pomice stone. Unfortunately the stone could notbe obtained. Professor Maddam of the University ofCatania advised Cassone to use brick and strong poz-zolana mortar for the dome, which would have yieldeda stronger structure than Noto’s typical mortar and stoneconstruction, but this suggestion was not taken.What could have been done to improve the perform-

ance of S. Nicolo? Masonry is extremely rigid and`brittle and therefore vulnerable to seismic damage. A

masonry structure is composed of thousands of piecesbound together by mortar. The challenge is how to aida masonry structure to move as a unit without breakingapart. In relation to domes, the famous treatise ofGiovanni PoleniMemorie istoriche della Gran Domedel Tempio Vaticano. e de’danni di essa, e de’ ristora-menti loro (Padova 1748) would have been a usefulsource for the builders of S. Nicolo. Poleniw24x explains`the mechanics of dome failure and discusses countermeasures like the use of iron chains to control the thrustsof domes. Poleni’s analysis of the effectiveness of theiron bars and chains used in St. Peter’s dome in relationto earthquakes is extensive. Iron rods had been used byBrunelleschi in his Ospedale degli Innocenti in Florenceto control the splaying of archesw25x. In the 16thcentury Giacomo della Porta used iron rods to controlhoop forces when he was completing the dome of St.Peter’s w26x. Later in the 17th century Francesco Bor-romini used iron chains to counter the thrust of hiscomplicated dome of S. Ivo alla Sapienzaw27x. Iron

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Fig. 11. S. Nicolo. Pulpit stairs cut into pier(photo: author).`

was used by Perrault in the 17th century in the easternfacade of the Louvrew28x. It was iron that was recom-mended as an antiseismic measure after the earthquakeof 1751 in Gualdo Tadino, Umbriaw29x. Giovann Bat-tista Mori recommended iron reinforcement after theCalabrian earthquake of 1783. When the church of S.Maria degli Angeli in Umbria was badly damaged in anearthquake in 1832, its dome was repaired with bandsof iron and the entire reconstruction was tied togetherby iron strapsw30x. But there is no such reinforcementin S. Nicolo.`It is important to remember that S. Nicolo was being`

reconstructed during a period in which earthquake resis-tant construction was known, even in Noto. In a treatiseof Christian Wolff’s Elementa Matheseos Universae(1715–1717) translated for Paolo Labisi in 1746 asElementi dell’Architettura Civile, there is a discussionof lateral bracing in roof systems and a depiction of the‘craticola’ used in foundations that served ‘ad impedirene’ tremuoti lo scompaginamento delle parti’ w31x.Books and articles on antiseismic designw32,33x likeEusebio Sguario’sSpecimen physico-geometricum deterraemotu ad architecturae (1756) were in circulationand because of the earthquakes of Lisbon in 1755 andCalabria in 1783 discussion of seismic problems becamemore common in the 18th centuryw34x. FrancescoMilizia in his Principii di Architettura Civile (1781)discussed antiseismic construction strategies. Commonsense solutions for limiting a building’s exposure toearthquake damage like building its dome in cane andplaster, reducing the dome’s height or eliminating itentirely seem never to have been discussed in Noto.

Such changes in traditional practice are not withoutprecedent: after the earthquake of 1783 the Bourbongovernment of Naples limited the height of buildingsbecause of seismic danger.Instead of improving the performance of S. Nicolo,`

19th- and 20th-century alterations may have accentuatedthe inherent weakness of the structure. With the eleva-tion of S. Nicolo to the status of Cathedral came the`necessity to create an even more exalted architecturalstatement. The chancel and apse were extended and thestone arches of the transept added. Of course, the statusof a Cathedral called for a high dome, so when the lastreconstruction occurred the engineer in charge, LuigiCassone, complied. Twentieth-century alterations fol-lowed the pattern of the 19th century. Church officialsdecided a pulpit stairway had to be excavated throughthe core of a fragile pier(Fig. 11). The laying of theflat roof of concrete prejudiced the structure in twoways. The weight of the roof was added to the structureand the tops of the former transverse arches were cut(Fig. 12). Rather than improving the performance of thestructure by providing a stiff diaphragm to distribute theloads, the roof may have aggravated the situation. Whenone side pier failed instead of a localized failure, theroof spread the damage by transferring load to the restof the nave, and thereby collapsing the entire interior.The Cathedral of S. Nicolo is an important and`

paradoxical symbol for the city of Noto. It representsthe Noto that aspired to be a center of culture duringthe waning years of the Baroque style in the 18thcentury. It records Noto’s last transformation in the 19thcentury into an aspiring ecclesiastical power. Noto’s

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Fig. 12. S. Nicolo. Collapsed roof showing 20th century alterations. In the 1950s transverse arches were cut, clerestory walls heightened and`concrete and steel roof with parapets added(photo: author).

citizens as well as the Church attempted to use the newCathedral to capitalize on religion to bring prosperity tothe city. The Cathedral in the 19th century embodied amemory of past importance of the 18th century as wellas Noto Antica. On the positive side, the reconstructionssymbolize Noto’s resolve to exist and continue as a city.Technically, there seems to have been pride and faith intraditional unadulterated stone masonry that wasreplaced again and again after earthquakes with littlechange in technology. Less positively, the reconstruc-tions could be seen as repetitions of failure withoutsignificant innovation or care taken to find a moreappropriate solution. These reconstructions seem to indi-cate a lack of interest in the challenges that must bemet when building in earthquake-prone Sicily. So thehistory of the Cathedral of S. Nicolo is a story of`tenacity and enduring tradition, but also of ignoranceand disregard for the lessons of the past.

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