Christian worship is a community activity, and form the earliest times, it was important to have suitable buildings where the congregation could assemble.As Christian communities grew in the Roman Empire after its establishment as the official religion, it became necessary to build large churches. The most suitable Roman architectural model was the basilica, which the Romans used as a legal court and audience hall. By the mid fifth century Rome had several splendid Christian basilicas, and the best preserved of these is the church of St. Sabina, built around 430 AD [1]. It follows the traditional basilical structure, with a high central section or nave separated by arcades of columns from the two lower side sections or aisles, and the altar replacing the dais or platform of the Roman magistrates. On top of the arcades are the side walls of the higher central section that have windows that bring light to the nave.This top side wall structure that rises above the roofs of the side aisles is called a clerestory. The roofs of all the sections are made of wood beams. After the decay of the city of Rome resulted from the barbarian invasions, the basilical building tradition remained with the Byzantine empire, and we have very good examples from the Italian city Ravenna, which remained part of the Byzantine empire until 756.
Figure 1: St. Sabina
Photo © wings.buffalo.edu/AandL/Maecenas
Another architectural form that was used in early Christian buildings is the central-plan church. In Roman times, this form was most often used for tombs or commemorative mausoleums. In Christian times, this style was more common in the Byzantine Empire, and a very good example that was easily accessible to Carolingian architects is the church of St. Vitale built in Ravenna around 540 AD (See Figure2). The main body of the St. Vitale church is in the form of outer and inner octagon structures separated by an aisle space at the ground level and a gallery above it. The inner octagon is composed of heavy piers topped by arches forming an arcade. On top of the arches there is a windowed clerestory wall that supports the church dome.This wall has eight windows.There are windows at all the levels of the outer octagon wall also. [2]
Figure 2: St. Vitale
Photo © Adrian Fletcher, www.paradoxplace.com
The royal place complex at Aachen was built between 789 and 808 under the direction of Charlemagne himself. In included a palace and a royal chapel. The whole complex was intended to evoke imperial Rome, with atriums and statutes. Pope Hadrian I had authorized Charlemagne to transport materials and decorations from building and decorations from buildings in Rome and Ravenna to use in his palace complex [3]. The palace chapel, although modified, preserves many original features. Iit has been incorporated into the structure of the present day Aachen cathedral.
The chapel was intended to be Charlemagne's burial site, so a central-plan style was a natural choice, imitating Roman mausoleums. Charlemagne had visited Ravenna, and the palace chapel design was clearly based on St. Vitale , but with some variations. Both churches use a two shell structure with an inner octagon. However, the outer shell at St. Vitale is also an octagon, while the one at Aachen is a sixteen-sided polygon. The sidewall of the inner octagon at St. Vitale are curved, while the ones at Aachen are straight. Both churches have a similar vertical structure with two levels, an aisle at the ground level and a gallery above topped by a windowed clerestory drum supporitng a dome [4]. The dome at Aachen is sectioned into eight segments and the one at St. Vitale is not. (See figures 2 and 3)
The nave at Aachen is supported by eight massive wedge-shaped piers at the corners of the octagon, linked by arches at the tops of both the aisle and gallery levels forming an octogonal arcade [5]. There are cylindrical columns, probably of Roman origins, in the arcade openings at both levels (See figure 4).
Figure 3: Palace Chapel Dome
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Figure 4: Palace Chapel Piers
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A truly innovative contribution of Carolingian architecture is what is called the westwork, which is the development of the western entrance of the church into an impressive façade, often with towers. Up until this time, the emphasis in Christian churches had been in the interior spaces, but Carolingian architects wanted to emphasize the grandeur of the empire in external visual statements.
The westwork of the Aachen chapel (See figure 5) consists of a tall vertical structure flanked by semicircular turrets, and with a monumental arch above the entrance. [6]
The architecture of Carollingian westworks achieved monumental proportions in the abbey church of Corvey and in other churches now destroyed, but revealed through archeological studies. [7]
Carolingian Basilicas
As indicated above, central-plan churches such as Charlemagne’s Palatine Chapel were rare outside of the Byzantine Empire, although a few were built as palace chapels and baptisteries. The prevalent church architecture in the West during the Carolingian period as well as the rest of the Middle Ages was the basilica.Several Carolingian basilicas have been preserved, including one built in Seligenstadt by Einhard, Charlemagne’s courtier and biographer, shown on figure 6.
The Roman basilicas traditionally used cylindrical columns (See Figure 1) made of a single large stone (monolith), which were not easy to obtain.An alternative is to use rectangular piers made of bricks. This technique, which was used at Seligenstadt and can be seen in figure 6, was not original to the Carolingians, but was often used from this time on. [8] Basilical roofs continued to be made of wood during the Carolingian period.
Westworks were common in Carolingian basilicas, becoming increasingly monumental, as can be seen in the Abbey church at Corvey from around 880 (See Figure 7).
[1] Roger Stalley, Early Medieval Architecture, (Oxford: Oxford University Press, 1999), 17-19.
[2] Robert Calkins, Monuments of Medieval Art, (Ithaca, NY: Cornell University Press, 1985), 32.
[3] Charles B. McClendon, The Origins of Medieval Architecture: Building in Europe, AD 600-900, (New Haven, CT: Yale University Press, 2005), 115.
[4] Robert Calkins, Medieval Architecture in Westerrn Europe, (New York: Oxford University Press, 1998), 70-71.
[5] Charles B. McClendon, The Origins of Medieval Architecture, 115.
[6] Robert Calkins, Medieval Architecture, 70-71.
[7] Hans Erich Kuback, Romanesque Architecture, (Milan: Electa S.p.A., 1978), 18-19.
[8] Roger Stalley, Early Medieval Architecture, 42-43.
Figure 5: Palace Chapel Entrance (Westwork)
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Figure 6: Seligenstadt Basilica
Photo © www.thais.it/architettura
Figure 7: Corvey
Photo © www.thais.it/architettura