History of medieval Arabic and Western European domes

The early domes of the Middle Ages, particularly in those areas recently under Byzantine control, were an extension of earlier Roman architecture. The domed church architecture of Italy from the sixth to the eighth centuries followed that of the Byzantine provinces and, although this influence diminishes under Charlemagne, it continued on in Venice, Southern Italy, and Sicily. Charlemagne's Palatine Chapel is a notable exception, being influenced by Byzantine models from Ravenna and Constantinople. The Dome of the Rock, an Umayyad Muslim religious shrine built in Jerusalem, was designed similarly to nearby Byzantine martyria and Christian churches. Domes were also built as part of Muslim palaces, throne halls, pavilions, and baths, and blended elements of both Byzantine and Persian architecture, using both pendentives and squinches. The origin of the crossed-arch dome type is debated, but the earliest known example is from the tenth century at the Great Mosque of Córdoba. In Egypt, a "keel" shaped dome profile was characteristic of Fatimid architecture. The use of squinches became widespread in the Islamic world by the tenth and eleventh centuries. Bulbous domes were used to cover large buildings in Syria after the eleventh century, following an architectural revival there, and the present shape of the Dome of the Rock's dome likely dates from this time.

Christian domes in Romanesque church architecture, especially those of the Holy Roman Empire, are generally octagonal on squinches and hidden externally within crossing towers, beginning around 1050. An example is the church of San Michele Maggiore in Pavia, Italy. St. Mark's Basilica in Venice, with its five domes on pendentives modeled on the Byzantine Church of the Holy Apostles, was built from 1063 to 1072. Domes on pendentives, apparently based upon Byzantine models, appear in the Aquitaine region of France after the beginning of the Crusades in 1095, such as the abbey church of Fontevrault, where Richard the Lionheart was buried. A series of centrally planned churches were built by the Knights Templar throughout Europe, modeled on the Church of the Holy Sepulchre, with the Dome of the Rock at their Temple Mount headquarters also an influence. Distinctive domes on pendentives were built in Spain during the Reconquista. Also built there were Christian crossed-arch domes similar to that of the earlier Great Mosque of Córdoba, such as at the Church of the Holy Sepulchre [eu] in Torres Del Río. Gothic domes are uncommon due to the use of rib vaults over naves and with church crossings usually focused instead by tall steeples, but there are examples of small octagonal crossing domes in cathedrals as the style developed from the Romanesque. The octagonal dome of Florence Cathedral was a result of the expansion plans for that church from the 14th century, a part of efforts in Tuscany to build domes with exposed external profiles.

The muqarnas dome type may have originated in Abbasid Iraq as single brick shells of large squinch-like cells, but it was popular in North Africa and Spain with more intricate cell patterns in stucco on a wooden inner shell. Two outstanding examples from the Moorish palace of the Alhambra in Granada, Spain, are the 14th century Hall of the Abencerrajes and Hall of the two Sisters. In 14th century Egypt, the Mamluks began building stone domes, rather than brick, for the tombs of sultans and emirs and would construct hundreds of them over the next two and a half centuries. Externally, their supporting structures are distinguished by chamfered or stepped angles and round windows in a triangular arrangement. A variety of shapes for the domes themselves were used, such as bulbous, ogee, and keel-shaped, and they included carved patterns in spirals, zigzags, and floral designs. Bulbous minarets from Egypt spread to Syria in the 15th century and would influence the use of bulbous domes in the architecture of northwest Europe, having become associated with the Holy Land by pilgrims. In the Low Countries of northwest Europe, multi-story spires with truncated bulbous cupolas supporting smaller cupolas or crowns became popular in the sixteenth century.

Early Middle Ages

Post-Roman areas

Although the chronology is uncertain for some examples, domes continued to be built in Italy throughout the Middle Ages. Dome construction appears to have stopped in the city of Rome in the middle of the 5th century, but there are dozens of Italian examples outside of Rome from the next few centuries.^[1] Continuing from late antiquity, domes in the early Middle Ages were built over centralized buildings such as baptisteries and martyria.^[2] Domed baptisteries built in 6th century Italy include Albenga Baptistery and those of Canosa di Puglia and Nocera Superiore.^[3] Other examples of domes may include the Sanctuary of San Prosdocimo in the Abbey of Santa Giustina in Padua (6th century), the Basilica of San Leucio at Canosa (6th century), the Basilica of San Salvatore in Spoleto (as early as the end of the 6th century), and the church of Sant'Ilario a Port'Aurea [it] in Benevento (no later than the 7th century).^[4]

The building projects of Theodoric the Great, the Ostrogothic king of Italy, largely continued existing architectural conventions. His Arian Baptistry in Ravenna (c. 500), for example, closely echoes the Baptistry of Neon built before it.^[5] The Mausoleum of Theodoric, however, was understood by contemporaries to be remarkable.^[5] Begun in 520, the 36-foot-wide (11 m) dome over the mausoleum was carved out of a single 440-ton slab of limestone and positioned some time between 522 and 526.^[6] The low saucer shape of the monolithic dome, which is estimated to be more than 230 tons of Istrian stone, may have been chosen to avoid radial cracking.^[7] The twelve brackets carved as part of the dome's exterior are thought to have been used to maneuver the piece into place. The choice of large limestone blocks for the structure is significant as the most common construction material in the West at that time was brick. It is likely that foreign artisans were brought to Ravenna to build the structure; possibly from Syria, where such stonework was used in contemporary buildings.^[6]

The Syria and Palestine area has a long tradition of domical architecture, including wooden domes in shapes described as "conoid", or similar to pine cones. When the Arab Muslim forces conquered the region, they employed local craftsmen for their buildings and, by the end of the 7th century, the dome had begun to become an architectural symbol of Islam. The rapidity of this adoption was likely aided by the Arab religious traditions, which predate Islam, of both domed structures to cover the burial places of ancestors and the use of a round tabernacle tent with a dome-like top made of red leather for housing idols.^[8] Early versions of bulbous domes can be seen in mosaic illustrations in Syria dating to the Umayyad period. They were used to cover large buildings in Syria after the eleventh century.^[9]

Umayyad Caliphate

The Dome of the Rock in Jerusalem, the earliest surviving Islamic building, was completed in 691 by Umayyad caliph Abd Al-Malik.^[10] Its design was that of a ciborium, or reliquary, such as those common to Byzantine martyria and the major Christian churches of the city.^[11] The rotunda of the nearby Church of the Holy Sepulchre, in particular, has a similar design and almost the same dimensions.^[12] The building was reportedly burned in the eleventh century and then rebuilt, which would still make it one of the oldest timber buildings in the world.^[13] The dome, a double shell design made of wood, is 20.44 meters in diameter.^[14] The dome's bulbous shape "probably dates from the eleventh century."^[9] Several restorations since 1958 to address structural damage have resulted in the extensive replacement of tiles, mosaics, ceilings, and walls such that "nearly everything that one sees in this marvelous building was put there in the second half of the twentieth century", but without significant change to its original form and structure. It is currently covered in gilded aluminum.^[15]

Byzantine workmen built the Umayyad Mosque of Damascus and its hemispherical dome for al Walid in 705. The dome rests upon an octagonal base formed by squinches.^[16] The dome, called the "Dome of the Eagle" or "Dome of the Gable", was originally made of wood but nothing remains of it. It is supposed to have rested upon large cross beams.^[17]

The placement of a dome in front of the mihrab of a mosque probably began with the rebuilding of the Prophet's Mosque in Medina by Umayyad Caliph Al-Walid. This was likely to emphasize the place of the ruler, although domes would eventually become focal points of decoration and architectural composition or indicate the direction of prayer. Later developments of this feature would include additional domes oriented axially to the mihrab dome.^[18]

In addition to religious shrines, domes were used over the audience and throne halls of Umayyad palaces, and as part of porches, pavilions, fountains, towers and the calderia of baths. Blending the architectural features of both the Byzantine and Persian architecture, the domes used both pendentives and squinches and were made in a variety of shapes and materials.^[19] A dome stood at the center of the palace-city of Baghdad and, similarly but on a smaller scale, there are literary accounts of a domed audience hall in the palace of Abu Muslim in Merv at the meeting point of four iwans arranged along the cardinal directions.^[20]^[21] The green dome at the center of the Round city of Baghdad covered the throne room of al-Mansur's palace and was topped by a statue of a horseman holding a lance. The dome collapsed in 941, well after the Caliph had moved his court to a suburban estate.^[22]

Muslim palaces included domical halls as early as the eighth century, well before domes became standard elements of mosque architecture. The early eighth century palace of Khirbat al-Minya included a domed gateway. The palace of Qasr Mshatta and a ninth century palace at Samarra included domed throne rooms.^[20] At Mshatta, "an elaborate entrance leads through a basilical hall to a domed triconch hall with an arcuated niche, presumably holding the caliphal throne, at the far end." This axial sequence of gateway, dome, and arcuated niche is found in early Islamic palaces into the Abbasid era, and the similar sequence of gateway, dome, and mihrab endured even longer in mosque architecture.^[23]

A domed structure covered a shallow pool in the main courtyard of the mid eighth century palace of Khirbat al-Mafjar. Similar examples at mosques, such as the domed fountains at the Mosque of Ibn Tulun (destroyed in 987 and replaced with a different structure), at Maarrat al-Numan, in Nishapur, Tripoli, and at the Mosque of Damascus seem to be related to this element of palace architecture, although they were later used as part of ritual ablution.^[24]

The calderia of early Islamic bath complexes at Amra, Sarraj, and Anjar were roofed with stone or brick domes.^[19] The caldarium of the early Islamic bath at Qasr Amra contains "the most completely preserved astronomical cupola decoration", a decorative idea for bath domes that would long continue in the Islamic world.^[25]

Although architecture in the region would decline following the movement of the capital to Iraq under the Abbasids in 750, mosques built after a revival in the late 11th century usually followed the Umayyad model, especially that of the Mosque of Damascus. Domed examples include the mosques at Sarmin (1305-6) and al-Bab (1305). The typical Damascus dome is smooth and supported by a double zone of squinches: four squinches create an eight sided transition that includes eight more squinches, and these create a sixteen-sided drum with windows in alternate sides.^[26]

Byzantine influence in Europe

Italian church architecture from the late sixth century to the end of the eighth century was influenced less by the trends of Constantinople than by a variety of Byzantine provincial plans.^[27] In Italy, there seems to have been a decline in the frequency of dome building between the 8th and 10th centuries.^[28]

Venice, Southern Italy and Sicily served as outposts of Middle Byzantine architectural influence in Italy. Venice's close mercantile links to the Byzantine empire resulted in the architecture of that city and its vicinity being a blend of Byzantine and northern Italian influences, although nothing from the ninth and tenth centuries has survived except the foundations of the first St. Mark's Basilica.^[29] This building was presumably similar to Justinian's Church of the Holy Apostles based on its layout, but how it was roofed is unknown.^[30]

In southern Italy, examples include the so-called baptistery of Santa Severina in Calabria, built sometime between the 4th and 11th centuries, the church of Church of Santa Maria di Gallana [it] in Agro di Oria, built sometime between 668 and the 9th century, the 8th or 10th century Tempietto di Seppannibale [it], the 10th century church of San Giorgio dei Martiri [it], and the 10th century church of San Pietro in Otranto [it].^[31] That southern Italy was reconquered and ruled by a Byzantine governor from about 970 to 1071 explains the relatively large number of small and rustic Middle Byzantine-style churches found there, including the Cattolica in Stilo and S. Marco in Rossano. Both are cross-in-square churches with five small domes on drums in a quincunx pattern and date either to the period of Byzantine rule or after.^[32]

The church architecture of Sicily has fewer examples from the Byzantine period, having been conquered by Muslims in 827, but quincunx churches exist with single domes on tall central drums and either Byzantine pendentives or Islamic squinches.^[33] Very little architecture from the Islamic period survives on the island, either.^[34]

With the crowning of Charlemagne as a new Roman Emperor, Byzantine influences were largely replaced in a revival of earlier Western building traditions, but occasional exceptions include examples of early quincunx churches at Milan and near Cassino.^[27] The extensive Byzantine use of domes on spherical pendentives after the sixth century did influence Carolingian architecture of the ninth and tenth centuries. Remains of spherical pendentives have been found in the church of Germigny-des-Prés.^[35]

Charlemagne's Palatine Chapel has a domed octagon design influenced by Byzantine models such as the Basilica of San Vitale in Ravenna, the Church of Sergius and Bacchus in Constantinople, and perhaps the Chrysotriklinos, or "golden reception hall", of the Great Palace of Constantinople.^[36]^[37] It has also been proposed that descriptions by returning travelers of the Dome of the Rock in Jerusalem, which was thought to have been the Temple of Solomon, served as the model.^[38] It was built at Charlemagne's palace at Aachen between 789 and its consecration in 805. The architect is thought to be Odo of Metz, although the quality of the ashlar construction has led to speculation about the work of outside masons.^[36] The octagonal domical vault measures 16.5 meters wide and 38 meters high. It was the largest dome north of the Alps at that time.^[39] The dimensions of the octagonal space match that of the 4th century octagonal Chapel of Saint Aquilino at the Basilica of San Lorenzo in Milan. The later central-plan cemetery church of St. Michael at Fulda was similar to the Aachen chapel, although simpler.^[40] Copies of the Palatine Chapel in Aachen include an octagonal church in Ottmarsheim [de], a chapel in Nijmegen [nl], and the Westbau of Essen Minster.^[41] The chapel inspired copies into the 14th century and remained a "focal-point of German kingship". The dome was rebuilt after a fire in 1656 and the interior decoration dates to around 1900.^[42]

Octagonal cloister vaults in northern Italy at this time may have been meant to reference the Palatine Chapel in Aachen. Examples include the chapel of S. Satiro in Milan from 876 (behind the later church of Santa Maria presso San Satiro), the baptistery at the church of Settimo Vittone [it] (889), and the baptistery of Agliate (c. 900).^[43]

Abbasid Caliphate

Although customarily a qadi would hear cases within the chief mosque, Abbasid Caliph al-Muhtadi reportedly built a domed hall with four doors for his role in administering justice. It was called the qubbat al-mazalim, or "The Dome of Justice", and built in 868-869.^[44]

A small nine-domed mosque in Balkh has been dated to the time of the Abbasids or Biyuds.^[45]

Emirate of Córdoba

Much of the Muslim architecture of Al-Andalus was lost as mosques were replaced by churches after the twelfth century, but the use of domes in surviving Mozarabic churches from the tenth century, such as the paneled dome at Santo Tomás de las Ollas and the lobed domes at the Monastery of San Miguel de Escalada, likely reflects their use in contemporary mosque architecture.^[46]

Maghreb

The Aghlabids

The dome of the Great Mosque of Kairouan (also called the Mosque of Uqba), built in the first half of the 9th century, has ribbed domes at each end of its central nave. The dome in front of the mihrab rests on an octagonal drum with slightly concave sides.^[47]^[48] The Great Mosque of Sfax in Tunisia was founded in the 9th century and later enlarged.^[49]

Almoravid dynasty

After the ninth century, mosques in North Africa often have a small decorative dome over the mihrab. Additional domes are sometimes used at the corners of the mihrab wall and at the entrance bay. The square tower minarets of two or more stories are capped by small domes. Examples include the Djamaa el Kebir mosque (probably of the 11th century), and the Great Mosque of Tlemcen (1303).^[49]

Ikhshidid dynasty

In Cairo, the martyrium of the Sharif Tabataba (943), an 18-meter square nine-domed open pavilion, is the earliest mausoleum whose plan has survived. The most common type, however, was a small domed cube.^[50] The use of corner squinches to support domes was widespread in Islamic architecture by the 10th and 11th centuries.^[51]

Caliphate of Córdoba

The Great Mosque of Córdoba, begun in 785 under the last of the Umayyad caliphs, was enlarged by Al-Hakam II between 961 and 976 to include four domes and a remodeled mihrab. The central dome, in front of the mihrab area, transitions from a square bay with decorative squinches to eight overlapping and intersecting arches that surround and support a scalloped dome.^[52] These crossed-arch domes are the first known examples of the type and, although their possible origins in Persia or elsewhere in the east remains a matter of debate, their complexity suggests that earlier examples must have existed. The nine bays of the Mosque of Cristo de la Luz, built about 50 years later, contain a virtual catalog of crossed-arch dome variations. After the 10th century, examples can also be found in Armenia and Persia.^[53]

Fatimid Caliphate

The Fatimids conquered Egypt from North Africa in 969 and established a new architectural style for their new Caliphate.^[54] Fatimid domes were either smooth or ribbed, hemispherical or stilted, and may or may not include a drum. When a drum was used, it was wider than the dome, octagonal, and part of a zone of transition.^[55] There were earlier Muslim domes in Eqypt, but none survive.^[56] The earliest Fatimid mosque, Al-Azhar, was similar to the earlier Mosque of Ibn Tulun but introduced domed bays at both ends of the qibla wall, in addition to the dome in front of the mihrab, and this feature was later repeated among the mosques of North Africa. Later alterations to the mosque have changed its original form.^[57] The earliest surviving Muslim dome over a mihrab in Egypt is that of Al-Hakim Mosque (990-1013) and the earliest mausoleum is the "Šaiḫ Yūnus" mausoleum, believed to have been built for Badr al-Jamali.^[56]

Earlier Coptic Christian domes primarily used squinches and only occasionally used pendentives, for example at Deir el-Muharraq, Dair Abū Fāna, and the narthex of Dair al-Abyad, but Fatimid domes used squinches exclusively.^[56] The squinches correspond to an exterior zone of transition, often stepped, when they are on top of the rectangular bay walls. Traditionally, Fatimid interior stalactite squinches were in one or two tiers and each interior tier would correspond to a step in the exterior transition zone. When the walls extended up past the squinches to the base of the dome, usually in Fatimid domes in Aswan [ar] and other areas outside of Cairo, no exterior zone of transition was needed. An example is the mausoleum of Al-imāra al-arabiyya in Aswan.^[58] Adding a tier of squinches made a dome taller, and Fatimid architecture begins a trend in Cairo toward ever taller buildings.^[55]

Egypt, along with north-eastern Iran, was one of two areas notable for early developments in Islamic mausoleums, beginning in the 10th century.^[59] Fatimid mausoleums, many of which have survived in Aswan and Cairo, were mostly simple square buildings covered by a dome. Domes were smooth or ribbed and had a characteristic Fatimid "keel" shape profile.^[60] The domes of the connected mausolea of Sayyida Atika and al-Gafari are examples.^[55] The first were built in and around Fustat. Those inside the city were decorated with carved stucco and contrast with the extreme simplicity of those outside the city, such as the four so-called Sab'a Banat (c. 1010) domed squares. Those at Aswan, mostly from the 11th century, are more developed, with ribbed domes, star-shaped openings, and octagonal drums with concave exterior sides which are corbeled outward at the top. They vary in plan as well, with domes sometimes joined with barrel vaults or with other domed mausoleums of different dimensions. The Fatimid mausoleum at Qus is in this Aswan style.^[61]

Other than the small brick domes used over the bay in front of a mihrab or over tombs, Fatimid domes were rare. An exception in size was the large dome over the Fatimid palace dynastic tomb.^[50] Literary sources describe royal domes as part of ceremonial processions and royal recreation.^[20] Examples of Fatimid palace architecture, however, described by travelers' accounts as their greatest achievement, have not survived. The ribbed or fluted domes introduced by the Fatimids may derive from a theme in earlier Coptic art, and would be continued in the later architecture of the Mamluks.^[62]

High Middle Ages

Hispanic Marches

The so-called first Romanesque style of churches in the early 11th century included examples in Spain with domes on squinches. The domes tend to be dark and sometimes included small windows at the base.^[63] The church of Santa Maria de Ripoll was consecrated in 1032, but was rebuilt after a fire in 1835. The church of Sant Miquel in Cruïlles was consecrated in 1035 and has a dome at its crossing covered on the exterior by a drum and short square tower.^[64] The church of Church of Sant Vicenç in Cardena was built by 1040 and there is another example at Corbera. The Corbera church may not have been intended to have a dome when the foundations were laid and the crossing bay was narrowed to create a square by the insertion of additional arches on the north and south sides. The dome was covered by a square belfry on the exterior.^[63] The small church of San Pablo in Barcelona has a central dome and triapsal arrangement resembling the churches of eastern Christianity.^[65]

East–West Schism

The schism between the churches of Constantinople and Rome was reflected in architecture. The Greek cross and domes of Byzantine architecture were found in areas of Byzantine cultural influence.^[66] The earliest existing large French dome is believed to be the pendentive dome built by 1075 over the crossing of the Collegiate Church of St-Martin at Angers [fr]. It reportedly incorporates "pottery" in its structure, a technique used in the late Roman period.^[67]

In Italy, the frequency, quality, and scope of dome construction increased beginning in the 11th century (although not in the city of Rome) and they were used in baptisteries, princely chapels, cathedrals, bell towers, and pieve churches.^[68] Examples include the baptistery of S. Ponzo Canavese [it] (c. 1005),^[69] the baptistery of the Basilica di San Vincenzo in Galliano (1007),^[70] the Baptistery of Biella [it] (c. 1040),^[71] and the baptistery of Novara Cathedral [it] (1040).^[43] The domed church of San Giovanni a Mare in Gaeta may have been built in the second half of the 11th century.^[72] At the Church of San Salvatore [it] in Barzanò, a third phase of construction added a hemispherical dome on squinches over the existing central bay of the building, possibly in the late 11th century.^[73] Octagonal cloister vaults appear "in connection with basilicas almost throughout Europe" between 1050 and 1100.^[74] The precise form differs from region to region.^[75] They were popular in medieval Italy, in brick.^[76]

Domes in Romanesque architecture were generally found within crossing towers at the intersection of a church's nave and transept, which concealed the domes externally.^[75] Called a tiburio, this tower-like structure often had a blind arcade near the roof.^[77] Romanesque domes were typically octagonal in plan and used corner squinches to translate a square bay into a suitable octagonal base.^[78] They were built across southern Europe in the 11th and 12th centuries and hundreds of examples under church crossing towers exist in Spain and southern France.^[2]

Republic of Venice

The Veneto region was strongly influenced by the architecture of Constantinople in the 11th century. On the island of Torcello, the Greek cross octagon style was used in the plan of the church of Santa Fosca [it].^[79]

In Venice, the second and current St. Mark's Basilica was built on the site of the first between 1063 and 1072, replacing the earlier church while replicating its Greek cross plan. Five domes vault the interior (one each over the four arms of the cross and one in the center). These domes were built in the Byzantine style, in imitation of the now lost Church of the Holy Apostles in Constantinople. Mounted over pendentives, each dome has a ring of windows at its base.^[80] These five windowed domes reflect the addition of windows (within tall drums) in the remodeled Byzantine original. However, the tall outer shells at St. Mark's were not added until after 1204.^[30] The later high wooden outer domes with lead roofing and cupolas were added to St. Mark's Basilica between 1210 and 1270, allowing the church to be seen from a great distance.^[80] In addition to allowing for a more imposing exterior, building two distinct shells in a dome improved weather protection. It was a rare practice before the 11th century.^[81] The fluted and onion-shaped cupolas of the domes may have been added in the mid-fifteenth century to complement the ogee arches added to the facade in the late Gothic period. Their shape may have been influenced by the open and domed wooden pavilions of Persia or by other eastern models.^[9] Initially, only the center dome had one.^[30]

Holy Roman Empire

The architecture of the areas of northern Italy that were a part of the Holy Roman Empire developed differently from the rest of the Italian peninsula.^[82] The earliest use of the octagonal cloister vault within an external housing at the crossing of a cruciform church may be at Acqui Cathedral in Acqui Terme, Italy, which was completed in 1067. This became increasingly popular as a Romanesque feature over the course of the next fifty years. The first Lombard church to have a lantern tower, concealing an octagonal cloister vault, was San Nazaro in Milan, just after 1075. Many other churches followed suit in the late 11th and early 12th centuries, such as the Basilica of San Michele Maggiore in Pavia (the coronation church of the Kingdom of Italy within the Holy Roman Empire) and the Basilica of Sant'Ambrogio in Milan.^[83] The Monastery of Capo di Ponte has a crossing dome that dates from about 1090.^[69] At Sant'Ambrogio, the original plan for the church did not include a domed crossing and it was modified to include one, as also happened at Pisa Cathedral (funding for which was provided by Emperor Henry IV in 1089 and Emperor Henry V in 1116) and Speyer Cathedral (the burial church of the Salian dynasty of Holy Roman Emperors).^[84] The crossing domes at Pavia, Pisa, and Speyer were all completed around 1080 but the exact order of precedence is unresolved.^[85]

The renovation of Speyer Cathedral, the largest of the Imperial Cathedrals of the Holy Roman Empire, was begun around 1080 by the Emperor Henry IV, soon after he had returned from a trip to Canossa in northern Italy. Although the church had only just been consecrated in 1061, Henry called upon craftsmen from across the empire for its renovation. The redesign included two octagonal cloister vaults within crossing towers, one at the east crossing with an external dwarf gallery and one at the west end. This was very soon imitated elsewhere and became the model for later Rhenish octagonal domes, such as those of Worms Cathedral (c. 1120–1181) and Mainz Cathedral (c. 1081–1239).^[86] Many German Imperial cathedrals feature domes at their crossings.^[87]

The domes of Pisa Cathedral and Florence Baptistery may be the two earliest domes in Tuscany and were the two largest until about 1150.^[88] Pisa Cathedral, built between 1063 and 1118, includes a high elliptical dome at the crossing of its nave and transept. The marble dome was one of the first in Romanesque architecture and is considered the masterpiece of Romanesque domes. Rising 48 meters above a rectangular bay, the shape of the dome was unique at the time.^[89] The rectangular bay's dimensions are 18 meters by 13.5 meters. Squinches were used at the corners to create an elongated octagon in a system similar to that of the contemporary Basilica of San Lorenzo in Milan and corbelling was used to create an oval base for the dome. The tambour on which the dome rests dates to between 1090 and 1100, and it is likely that the dome itself was built at that time. There is evidence that the builders did not originally plan for the dome and decided on the novel shape to accommodate the rectangular crossing bay, which would have made an octagonal cloister vault very difficult. Additionally, the dome may have originally been covered by an octagonal lantern tower that was removed in the 1300s, exposing the dome, to reduce weight on foundations not designed to support it. This would have been done no later than 1383, when the Gothic loggetta on the exterior of the dome was added, along with the buttressing arches on which it rests.^[90]

An aspiring competitor to Pisa, the city of Florence took the opposite side in the conflict between Pope and Emperor, siding with the Pope in Rome. This was reflected architecturally in the "proto-renaissance" style of its buildings.^[91] The eight-sided Florence Baptistery, with its large octagonal cloister vault beneath a pyramidal roof, was likely built between 1059 and 1128, with the dome and attic built between 1090 and 1128. The lantern above the dome is dated to 1150.^[92] It takes inspiration from the Pantheon in Rome for its oculus and much of its interior decoration, although the pointed dome is structurally similar to Lombard domes, such as that of the later Cremona Baptistery. Its ratio of wall thickness to external diameter is about 1/10, in accordance with the rules of dome proportion followed until the 17th century. One of the most important religious buildings in Florence, the proportions of its dome were followed by the nearby dome of the Cathedral of Santa Maria del Fiore that was built by Brunelleschi centuries later. The polygonal dome was built with a wooden tension ring at about 23 meters high, too high to counteract the spreading forces, and a lower iron ring was added in 1514.^[93]

Smaller domed centralized buildings from this time include those of S. Fermo di Sopra (c. 1125), the Church of Santa Maria in Solario [it] (c. 1130), the Baptistery of Riez [fr], and the Baptistery of San Giovanni Battista in Agrate Conturbia [it] (c. 1135).^[94]

The crossing dome at the Church of St. Trophime in Arles is beneath a large square tower.^[95]

Kingdom of France

The earliest example of a church with a transept in the Aquitaine region of France is the Church of Saint-Martin de Layrac [fr] (1063-1102), with a dome at the crossing.^[96]

The 11th and 12th century Cathedral of Le Puy uses an unusual row of six octagonal domes on squinches over its nave, with the domes at the western end being at least a century later than those at the east end. A seventh dome is located in the normal position for a Romanesque dome on squinches: over the crossing. Other examples of this use over naves are rare and scattered. One is the large church of Saint Hilaire at Poitiers, which seems to have been influenced by Le Puy Cathedral. In 1130, its wide nave was narrowed with additional piers to form suitable square bays, which were vaulted with octagonal domes whose corner sides over trumpet squinches were so narrow that the domes resemble square cloister vaults with beveled corners.^[97]

The crossing dome on squinches at the abbey church of Tournus may date to the 11th century. The Basilica of Saint-Martin d'Ainay has similar features. The largest church in France was Cluny Abbey, but it has been destroyed.^[98] The surviving transept arm of Cluny Abbey, built in the early 12th century, has an octagonal dome on trumpet squinches beneath an octagonal tower and spire and flanked on either side by barrel vaults.^[99] Autun Cathedral has a similar nave arrangement to that of Cluny Abbey.^[100]

In Auvergne, there are several Romanesque churches with domed crossings that use squinches, with the dome supported by "flying screen" walls at the crossing bay and hidden on the exterior beneath octagonal towers with buttressing "shoulders" on two sides. Examples include the church of St. Saturnin [fr] and the Sainte-Marie de Cruas Abbey [fr], which has a rotunda over the domed crossing.^[101] At Avignon Cathedral, probably from the middle of the 12th century, the rectangular crossing bay is narrowed to a square by means of two sets of four arches on opposite sides for the dome on squinches.^[102]

Duchy of Apulia and Calabria

In southern Italy, the Basilica of San Sabino [it] in Canosa di Puglia was built around 1080 with five domes over its "T-shaped layout", with three domes across the transept and another two out over the nave.^[103] Its cruciform plan, use of domes, and the later addition of an external mausoleum suggest that it may have been a Norman analog to the Byzantine Church of the Holy Apostles. It appears to have inspired a series of churches in Apulia with domed naves.^[104] The date of construction has been challenged as being decades too late. The multi-domed churches of Cyprus have been proposed as the inspiration for the basilica's domes and for the three-domed naves of later churches in the region, which date mostly from the period of Norman rule, but this is also a topic of debate. San Benedetto at Conversano [it], the Ognissanti of Valenzano [it], San Francesco at Trani [it], and the Cathedral of San Corrado at Molfetta [it] were built in the 11th to 13th centuries with pendentive domes. San Corrado also incorporates "squinch-like niches" between the pendentives and drums of two of its three domes.^[105] The domes at Valenzano were covered by low pyramids that were rebuilt in the 1960s. The Cathedral of San Corrado was built around the year 1200. The town of Balsignano [it] has the ruin of a small domed church that reflects a mixture of eastern and western influences.^[106]

Crusades and Reconquista

The Crusades, beginning in 1095, also appear to have influenced domed architecture in Western Europe, particularly in the areas around the Mediterranean Sea.^[107] The Mausoleum of Bohemond (c. 1111–18), a Norman leader of the First Crusade, was built next to the Basilica of San Sabino in the southern Italian province of Apulia and has a hemispherical dome in a Byzantine style over a square building with a Greek cross plan.^[108] The dome had been covered by a pyramidal roof, according to a 1780s engraving, and the portion above the octagonal drum is a restoration.^[109]^[110] The Padua Baptistery is believed to have been built contemporaneously with the 1120s reconstruction of Padua Cathedral, a revision of the traditional foundation date of 1260. It has a dome on pendentives spanning an 11.6 meter square space, with a small altar chapel through the eastern wall. It served as a model for the later Old Sacristy of San Lorenzo.^[111]

The Crusaders built several churches in Jerusalem during the 12th century. The most complete is the Church of Saint Anne, which has a small crossing dome.^[112]

Influence of the Church of the Holy Sepulchre

The Church of the Holy Sepulchre in Jerusalem seems to have had a wooden dome in two shells up to the 12th century, with some interruptions. After their establishing control of the city, the crusaders added a choir with a dome next to the existing rotunda.^[113] The French Romanesque addition replaced the eastern apse of the rotunda and a courtyard marking the center of the world and was consecrated on July 15, 1149, the fiftieth anniversary of the capture of the city. The new dome's diameter of 10.4 meters was half that of the rotunda and it rested on four pointed arches on four pillars. It served as the coronation site for the crusader kings of Jerusalem and its relation to the larger dome over the rotunda may have been intended to mirror the relationship between the domes of the Dome of the Rock and the Al-Aqsa Mosque on the Temple Mount.^[114]

The rotunda itself was covered by a conical structure from the 12th to the early 19th century. Pisa Baptistry was built in 1153 with a truncated cone in clear imitation of the Holy Sepulchre; an outer dome shell was added in the 14th century. The domed baptisteries of Cremona (1176) and Parma (1196) also appear to have been influenced by the rotunda.^[115] The 12th century rotunda of the Holy Sepulchre at Santo Stefano, Bologna, and the basilica at Neuvy-Saint-Sépulchre are imitations of Jerusalem's Church of the Holy Sepulchre although, like many of the imitations across Europe, they differ in their details, including their domes.^[116] Most of these "so-called 'copies'" have a dome or domical vault. An example is a church at Almenno, Italy, which has a stone dome resting on eight supporting columns.^[2]

The Dome of the Rock and the Al-Aqsa Mosque on the Temple Mount of Jerusalem were taken by the crusaders to represent the Temple of Solomon and the Palace of Solomon, respectively. The Knights Templar, headquartered at the site, built a series of centrally planned churches throughout Europe modeled on the Church of the Holy Sepulchre, with the Dome of the Rock also an influence.^[117] Examples include the church of the Vera Cruz at Segovia [es], the church of the Convento do Cristo at Tomar, a rotunda church in Paris destroyed during the French Revolution, and Temple Church in London. The Church of Saint Mary of Eunate was a pilgrims' burial church, rather than a Templar church, but may have been influenced by them.^[118] The Church of the Holy Sepulchre in Cambridge and the Templar’s Chapel at Laon [fr] contain ribbed domes.^[119]

Kingdom of Italy in the Holy Roman Empire

Churches in northern Italy after 1100 were designed with vaulting from the outset, rather than as colonnaded basilicas with timber roofs and, like the Rhenish imperial cathedrals, many have octagonal domes with squinches over their crossings or choirs. Examples include Parma Cathedral, rebuilt around 1130, and Piacenza Cathedral (1122-1235).^[120] Another example is the domed church of San Fedele in Como (11th to 12th century), similar to the church of St. Maria im Kapitol. The Baptistery of Parma, one of the largest baptisteries, was begun in 1196 and has dome frescoes dating from 1260 onwards.^[77]

The Old Cathedral of Brescia was likely built in the first quarter of the 12th century and has a dome over a meter thick, made of heavy stone at the bottom and lighter porous stone at the top.^[121] In Tarquinia, the oval stone dome on squinches over the church of San Giacomo (c. 1121–1140) may have been inspired by the dome of Pisa Cathedral. A dome on pendentives in Tarquinia was completed around 1190 as part of the cathedral of Sta. Maria di Castello and was similar to others in Tuscany and the Veneto. It was destroyed by an earthquake in 1819.^[122]

The dome of the Basilica of San Lorenzo in Milan, a tetraconch building with a central space 23.8 meters square, was rebuilt in the Romanesque style after a fire in 1124. Much admired in the Renaissance, its dome collapsed in 1573 and was rebuilt with the present cloister vault.^[123] Documentary evidence indicates that the Romanesque dome of San Lorenzo was a thin hemisphere of light material over a cube of space about 23.8 meters (40 Milanese braccia) on each side. The dome was supported by four corner squinches resting on the four exedrae arches of the square space with a further eight smaller squinches between each of them to create a sixteen-sided base. It was covered on the exterior by a cylindrical or polygonal drum and timber roof. The exterior drum was likely polygonal, with eight or sixteen sides, and had two levels of dwarf galleries beneath a cornice row of hanging arches. Evidence remains in the building's eastern corner towers of flying buttresses extending diagonally to the drum. The existence of a small lantern at the top of the dome is uncertain and the date the dome was completed is unknown.^[124]

The cathedral of Sovana (1153-1175) and the church of San Salvatore at Terni (about 1200) were constructed with local materials and have precedents in the region.^[125] The alternating stone and brick rings of the dome over the Rotuna of Montesiepi [it] at the Abbey of San Galgano are unusual but may be part of Tuscan decorative polychrome banding.^[126] It was built in the 1180s as a commemorative chapel with a hemispherical dome over a cylindrical rotunda and the top 16 rings are all in brick, giving the impression of an oculus at the top of the dome.^[2]

Kingdom of France and the Angevin Empire

The crossing dome at Obazine Abbey has pendentives, which became popular in France throughout the 12th century. By the middle of the 12th century, the use of drums with windows beneath the domes allowed in more light. Octagonal drums were preferred. Examples include the church of La Dorat [fr] in the Limousin region and the Church of Saint-Léonard-de-Noblat [fr].^[127] Other examples include the crossing domes of the church of St. Étienne at Nevers [fr] (c. 1097), the Basilica of Notre-Dame du Port (built in the 11th and 12th centuries), the basilica at Orcival [fr] (12th century), and the church of Saint-Nectaire [fr]. In the latter three examples, the crossing dome is supported on the north and south sides by an adjacent half or full barrel vaults.^[128] Another example of a crossing dome on an octagonal drum and pendentives that is part of a tall lantern tower is Saint-Barthélémy Church of Bénévent-l'Abbaye [fr].^[102]

In the Aquitaine region of southwest France, there are a large number of unusual domed Romanesque churches; over 250 in the Périgord region alone. The area is far from ports with regular contact with the East and the source of influence is not entirely settled.^[129] A study in 1976 of Romanesque churches in the south of France documented 130 with oval plan domes, such as the domes on pendentives at Saint-Martin-de-Gurson, Dordogne [fr] and Balzac, Charente.^[130] The oval shape appears to have been a practical solution to rectangular crossing bays.^[131] The use of pendentives to support domes in the Aquitaine region, rather than the squinches more typical of western medieval architecture, strongly implies a Byzantine influence.^[132] The oldest French pendentives are built in horizontal courses, rather than courses normal to the curve. This may have been done to better spread the weight of each course and also allow for a lighter wooden centering to be used during construction.^[133]

Between the Garonne and Loire rivers there are known to have been at least seventy-seven churches whose naves were covered by a line of domes. Half of them are in the Périgord region. Most date to the twelfth century and sixty of them survive today.^[134] That the domes in this area were arranged in linear series has suggested the contemporary architecture of Cyprus as the inspiration, which was located on a pilgrimage route to the Holy Land.^[135] Cyprus had developed its own style of domed basilica during its period of neutrality between Byzantine and Arab rulers, using three domes of roughly equal size in a line over the nave and very little lighting. There are indications of a connection between Aquitaine and Cyprus just after the First Crusade.^[136]

The earliest of these French churches may be Angoulême Cathedral, built from 1105 to 1128. Its long nave is covered by four stone domes on pendentives, springing from pointed arches, the last of which covers the crossing and is surmounted by a stone lantern.^[137]^[138] Possible earlier domes may have existed at the church of Saint-Astier, Dordogne, which was founded in 1010 although little of the original construction remains, and at Saint-Avit-Sénieur (c. 1117), whose original three domes were replaced with "domed up Anjou vaults" in the 13th century.^[139] The westernmost of the Angoulême domes is the earliest, constructed between 1100 and 1125. Four small recesses at the base of each nave dome, just above the cornices, was likely used to secure wooden centering formwork during construction. Later stone domes in the region have four small windows in a similar location that may have been used in the same way.^[139] The domes of the church of St. Étienne at Périgueux [fr] preceded the larger ones at Cahors Cathedral.^[140] St. Étienne originally had four domes, but two were destroyed in the 16th century. Of the remaining two, the earlier one was completed around 1125 the later one by 1163.^[139] Cahors Cathedral (c. 1100–1119) covers its nave with two large domes in the same manner and influenced the later building at Souillac [fr].^[137] The domes at Cahors have a diameter of more than fifty feet.^[140] The abbey church at Fontevrault served as a burial place for Plantagenet royalty, including Richard the Lionheart, and is one of the most impressive examples. The earlier domed crossing is preceded by a wider nave covered by four domes, which was begun in 1125. The pendentives are original, but the four nave domes are modern replacements from about 1910.^[141] Originally designed as a three-aisled hall church with barrel vaults, after the choir was completed the nave was redesigned with piers to support the line of domes spanning the full width. Likewise at the Abbaye aux Dames in Saintes, the abbey church was remodeled during construction to allow for the domes.^[142]

The cathedral of S. Front at Périgueux was built c. 1125–1150 and derives its five-domed cruciform plan ultimately from the Church of the Holy Apostles in Constantinople.^[137]^[143] One of the domes covers part of the choir, the rest of which is covered by a barrel vault and apse half-dome, although most domed churches in the region used only a barrel vault and apse half-dome for the choir.^[144] The domes differ from normal Byzantine practice in the use of stone, rather than a lighter material such as brick, and that difference may help explain the other differences, such as the domes being slightly pointed and at least semicircular, rather than segmental, springing from a distance set back from the circle formed by the pendentives, rather than directly from the circle, and resting on pendentives with complex curves that begin at the lower side of the supporting arch voussoirs, rather than quarter-circle pendentives beginning at the upper side.^[133] The S. Front domes had dressed stone only on the lowest levels prior to alterations by Paul Abadie in the 19th century. The lanterns on the domes at Souillac were likewise added by 19th century restoration.^[145] There are indications that the domes were originally covered by a wooden roof.^[146]

Gothic rib vaulting superseded the use of domes in south-west France after the 12th century. The church at Saint-Avit-Sénieur appears to have been designed for domes but they may never have been built. The nave is covered instead by ribbed Angevin style vaults. The "domical shape of Angevin vaults", like those seen in Angers Cathedral, may be due to the influence of Romanesque domed churches.^[142] The foundations of Bordeaux Cathedral indicate that it originally had a nave covered with a line of three domes like those of Angoulême Cathedral but it was rebuilt in the 13th century with a vaulted ceiling.^[147]

Kingdom of León and the Emperors of all Spain

The remains of a crossing tower on the French Church of Saint-Jean de Montierneuf from about 1140 suggest an origin for some Spanish domes in a Romanesque and transitional Gothic style.^[148] The architectural influences at work here have been much debated, with proposed origins ranging from Jerusalem, Islamic Spain, or the Limousin region in western France to a mixture of sources.^[75] The disappeared Romanesque dome over the Cathedral of Santiago de Compostela has also been proposed.^[149]

During the Reconquista, the Kingdom of León in northern Spain built three churches famous for their domed crossing towers, called cimborrios, as it acquired new territories. The Cathedral of Zamora, the Cathedral of Salamanca, and the collegiate church of Toro were built around the middle of the 12th century. All three buildings have stone umbrella domes with sixteen ribs over windowed drums of either one or two stories, springing from pendentives. All three also have four small round towers engaged externally to the drums of the domes on their diagonal sides.^[150] A later related dome is that over the chapter house of the Old Cathedral of Plasencia.^[151] The early Gothic Cathedral of Évora in Portugal has been proposed as a late addition to the set.^[149] Perhaps the masterpiece of the series, the Salamanca crossing tower has two stories of windows in its drum. Its outer stone fish-scale roof lined with gothic crockets is a separate corbelled layer with only eight lobes, which applies weight to the haunches of the sixteen-sided inner dome.^[152] The vaulting over the nave of the old Salamanca Cathedral is covered by domes supported by diagonal ribs in the western bays and Anjou-style domed-up rib vaults in the two eastern bays.^[153]

The dome of the church of San Millán [es] in Segovia is an octagonal crossed-arch dome on squinches that may have been made with concrete around the middle of the 12th century.^[154] Another unusual Spanish example from the late 12th or early 13th century is the dome of the Church of the Holy Sepulchre [eu] in Torres Del Río, on the Way of St. James. The Way, a major pilgrimage route through northern Spain to the reputed burial place of St. James the Greater, attracted pilgrims from throughout Europe, especially after pilgrimage to Jerusalem was cut off. The difficulty of travel to Jerusalem for pilgrimage prompted some new churches to be built as a form of substitute, evoking the central plan and dome of Jerusalem's Church of the Holy Sepulchre with their own variant. The dome in this case, however, is most evocative of the central mihrab dome of the Great Mosque of Cordoba. Over an octagonal room, the stone dome is formed by sixteen ribs, eight of which intersect with one another in a star pattern to define a smaller octagon at the center of the dome.^[155] This is one of a number of Christian crossed-arch dome examples in Spain and the south of France from the end of the 12th century, with patterns based upon the square or octagon. Other examples include the domes of San Miguel de Almazán, Santa Cruz de Olorón [fr], and San Blas Hospital [fr]. Contemporary Islamic examples in Spain and North Africa are distinguished from the Christian by the use of thinner and more numerous arches, such as those of the Alcázar of Seville, the Villena Castle in Alicante, the Great Mosque of Taza, and the minaret of Koutoubia Mosque. The style experienced a revival in early 16th century Spain when one of the crossed-arch domes of the Great Mosque of Córdoba was used as the model for domes at Zaragoza, Teruel, and Tarazona.^[156]

Kingdom of Sicily

The Christian domed basilicas built in Sicily after the Norman Conquest also incorporate distinctly Islamic architectural elements. They include hemispherical domes positioned directly in front of apses, similar to the common positioning in mosques of domes directly in front of mihrabs, and the domes use four squinches for support, as do the domes of Islamic North Africa and Egypt. In other cases, domes exhibit Byzantine influences with tall drums, engaged columns, and blind arcades.^[157] The influence of the domed mosques of the Aghlabids has been cited to explain the design of the domes; representative examples of Islamic domes from North Africa can be seen in the Al-Hakim Mosque and the Great Mosque of Sousse.^[158]

Domes were used in a variety of compositions and were often not the center or focus of the architecture. In the Val Demone region, the churches of Santa Maria in Mili [it] (1090, but rebuilt in the 15th century), San Pietro in Itala [de] (1092–1093, but rebuilt), and Santi Pietro and Paolo in Casalvecchio (1116, but rebuilt and restored in 1172) are well-preserved. The three domes on squinches of Santa Maria in Mili San Pietro [it], one of the first Norman buildings, are close together in a row above the prothesis, presbytery, and diaconicon, with the largest and tallest in the middle. The church of San Pietro in Itala has a central, tower-like dome. The church of Santi Pietro and Paolo in Casalvecchio has two domes, with a smaller eight-sided umbrella dome with muqarnas-like supports in the space before the altar and a larger umbrella dome on squinches over the nave.^[159] The dome over the nave has a circular base and the dome over the altar has an octagonal base.^[160]

Examples at Palermo include the Palatine Chapel (1132–1143), La Martorana (c. 1140s), and Zisa, Palermo (12th century).^[161]^[162] The church of San Giovanni degli Eremiti has five domes in a T-shaped arrangement and the Church of San Cataldo has three domes on squinches, with both showing clearly Islamic influence.^[163]