HOW THE BASILICA BECAME A CHURCH.

In the Middle Ages the most important architectural task was church building. Whether parish churches or monasteries, simple churches for mendicant orders or magnificent cathedrals, the requirements for sacred buildings created innumerable large building projects all over Europe. With the basilica form church building imposed a building type that had originally fulfilled quite different purposes. The basilica is not a medieval invention-they had already been developed in ancient Rome and frequently built there. In the Roman era basilicas served as assembly halls for all kinds of uses. They were law courts, places of worship, and even market halls. When Emperor Constantine acknowledged Christi­anity at the beginning of the fourth century, a lot of new church building began. The Emperor himself, or his bishops, founded churches, and soon the basilica was established as the building form for this task. Santa Sabina in Rome is a basilica from the early Christian period . The church was built c. 430 A. D. on the Aventine Hill, on the site where the house of the martyr St. Sabina is thought to have stood.

A glimpse of the interior shows the orientation of the church: the longitudinal axis ends with a semi-circular space called the apse, and the building is orientated towards this. The nave has a flat ceiling, and the upper section of the walls is set with round-headed windows. Below, round arches create the entrance to the side aisles. This sums up the characteristics of a basilica: it consists of a high central aisle illuminated independently by windows, and lower side aisles, which are separated from the central section by arches. The easterly end of the church is formed by the semi-circular apse, which contains the altar.

In medieval Christian teaching, each architectural component of a basilica had a particular meaning. This started with the orientation of the buildings:basilicas face eastwards as, according to Christian belief, this means they point in the direction of the Holy Land. The clear orientation of these elongated buildings contrasts with centrally planned buildings, which are based on a symmetrical ground-plan, taking the form of a circle or an octagon, for example. According to the orientation of a basilica the en­trance faces west, while the choir is located in the east of the church. The west facade with the main entrance was understood to be the entrance to the house of God and was accentuated with towers or a porch.

In the Romanesque period the basilica was finally established as the building form for churches. Yet the concept of Romanesque is a 19th-century invention. It is understood to mean art from the eleventh to the mid-thirteenth centuries, a period when architecture reverted to forms from Roman Antiquity. In fact it was only after the turn of the millennium that clear correspondences in artistic production emerged in France, Spain, Italy, Germany, and England, despite regional differences. It is an aspect of this inter­national common ground in Romanesque architec­ture that the basilica is the most frequently used type of sacred building. Another characteristic of the architecture of this period is the round arch. The construction of arches, which had already been employed in Roman architecture, was taken up again by the architects of the Romanesque period. In church interiors there were to be no more straight-headed openings, but instead round arches supported by columns and pillars. The construction of stone roofs was also tackled using round arches. The vaulting, firstly of the side aisles, then of the church's central aisle as well, is a further character­istic of the Romanesque style. Sculptural elements attached to the architecture were also used more and more at this time: the portals and facades of Roma­nesque buildings were shaped in a rich sculptural and ornamental way. An excellent example of this is the Portico de la Gloria on the west facade of the great pilgrimage church of Santiago de Compostela in Spain, which has been the main entrance to the basilica since the late twelfth century.

One of the first buildings that shows the essential features of Romanesque architecture is the cathedral in Speyer, Germany, which was begun in the years after 1020 . The plan of the church shows the basilica form. In addition, between the nave and the choir a section of the building has been intro­duced at right angles: this is the transept, a typical feature of Romanesque sacred architecture. Thus the ground-plan of the body of the church forms a cross, The cathedral in Speyer was planned as the burial place for the Salian emperors: Conrad II, who ascended the throne as first Salian emperor in 1027, ordered work to begin on his church around 1030. The entrance lies within a massive westwork (west-facing entrance section), its central axis surmounted by a tower. Beyond this is a three-aisled nave. The transept intersects with the nave in front of the east-facing, semi-circular choir. This point, at which the spatial axes of nave and transept meet, the so-called crossing, is marked on the outside of the building by a tower. Two further towers are attached to the choir area, which can be recognized on the plan as a semi-circle. Like many Romanesque church build­ings, Speyer Cathedral seen from the outside looks as if it has been made up of individual architectural elements joined together. This would change with the advent of the Gothic cathedrals. Even in the late Middle Ages, however, the ground-plan of the basilica remained dominant. This was the case too for Amiens Cathedral, which was begun in the period of High Gothic, around 200 years after Speyer.

In its ground-plan it is above all the east-facing part of the church which is emphasized by comparison with Romanesque buildings: already the transept has three aisles, attached to which are even more vaulted areas of the nave, which in its transition to the choir, has five aisles. For a long time now the choir area has no longer been just a semi-circular apse: instead, at­tached to this is an ambulatory, which is surrounded by more semi-circular apses. Even if the shape of the choir in particular in Gothic cathedrals was essenti­ally more extravagant than in Romanesque churches, the basic form of the basilica remained the most influ­ential in Western church architecture for centuries.

VAULTED CEILINGS.

In Greek temples horizontal stone beams were supported by tall columns, as exemplified by the famous Parthenon built in the fifth century B.C. on the Acropolis in Athens. With the arrival of Roman architecture the curved arch won its place alongside the straight beam. For functio­nal buildings such as aqueducts, pillars supporting arches were used equally, as in the building of the Roman Colosseum . And alongside the development of the arch in the Roman period we see that of the curved, self-supporting stone ceiling which covers a space—the vault. The different variations on the vault, whose com­mon basic form is the arc, permit a wealth of spatial solutions, from architecturally simple barrel-vaulted spaces via dome constructions to Gothic variations using stellar vaulting and fan vaulting. The dome flourished during the period of Byzantine architec­ture. One of the most important domed churches is the Hagia Sophia in Istanbul.

It was above all the Romans who developed the use of vaulting in architecture. But knowledge of how to create vaults across spaces was not used in the first instance in temple building-where they preferred to stick to Greek models-but in the architecture of Roman baths. Every town in the Roman Empire had its own public baths, which were an important part of social life. The lofty halls of the baths were vaulted, as shown for example in the reconstruction of the huge site of the Baths of Caracalla from the early 3rd century A.D. While the central bathing rooms were vaulted with a hemispherical dome, the elongated rooms were barrel-vaulted, with many arcs placed alongside each other. If two barrel-vaulted rooms of equal height came together, this created a groin vault. The Romans developed the groin vault out of the barrel vault and used it to cover wide spaces. The vault was used even for places of religious worship such as temples and early Christian basil­icas, particularly from late Antiquity onwards. The Pantheon in Rome, a temple dedicated to all the gods, with its dome of over 43 meters in diameter, occupies a special place in the dome architecture of ancient Rome.

At first the groin vault maintained its position of great importance in medieval architecture. In church building after the turn of the millennium a plan with three aisles was the norm, with two side aisles flanking a wider, higher central aisle. In Romanesque churches, or basilicas, as these three-aisled buildings are called, the narrower side aisles were the first to be vaulted, while the central aisle retained its flat ceiling. The use of vaulting in church aisles is one of the great innovations of Romanesque architecture. Where groin vaulting was introduced in Romanesque architecture, the space to be covered was at the outset still very small. The architects began with small spaces and gradually vaulted the entire space of the church.

In Speyer Cathedral the vaulting of the individual architectural sections similarly took place in several stages. The cathedral, the burial place of the Salian* emperors and kings, is the greatest early Romanesque building in the Western world. The monumental three-aisled basilica was rebuilt and extended many times, and in this process it was gradually filled with vaulting. Around the middle of the eleventh century the groin vaults in the under­ground burial chapel, the crypt, as well as those in the towers and side aisles of the nave were com­pleted. Because of its ridges, the intersecting lines of the surfaces of the vaults which arise due to the fusion of two barrel vaults, this kind of vaulting is also known as cross vaulting. The ridges, which run diagonally, divide the vault into four sections that ensure an equal distribution of the forces created by the vault. In spite of the well-developed technology, several decades passed before the vaulting of the large expanse of the nave was attempted at Speyer Cathedral.

The nave was initially flat-ceilinged and was only later covered with groin vaulting in the years around 1100.The first time vaulting was used extensively was in the building of Durham Cathedral in England.

This three-aisled basilica was begun in 1093, and was completed a good three decades later. This enormous church, 143 meters long, is characterized by strong walls and massive round arches. The architectural forms and technology of cathedral building were brought to England by the Norman conquerors, when William, duke of Normandy, occupied the country in 1066. As a result Norman building styles spread into areas north of the English Channel. In 1100 the choir of the church saw the introduction of a high vault, which offered a clear contrast to the massive forms of the Romanesque style. The nave vault was finally introduced instead of the orig­inally planned flat ceiling. By 1133 vaulting had been perfected, with the addition of a new type of vault. Thin ridges divide the areas of the vaulting into four sections and below these edges thin ribs are insert­ed—unlike the crypt of Speyer Cathedral. In this rib vault the rod-like ribs bear the thrust and the cells are stretched between them. In Durham Cathedral the thrust of the vault is diverted by powerful round pillars whose diameter measures as much as six meters. They are decorated with different patterns, including the zigzag form typical of Norman art. The rib vault soon developed into the standard type of vaulting for the great Gothic cathedrals. By sup­porting the vaults by means of buttresses and flying buttresses, architects were able to attain spectacular heights with their vaults. The Gothic rib vault was best suited to cover all types of spaces. Its use of pointed arches gave the architect more creative freedom as he could vary the width and height of the vault's sections.

The church of Saint-Denis in Paris is one of the first to be built using rib vaulting in the choir. Its high interior was completely vaulted as early as the first quarter of the twelfth century. In the cathedral of Notre-Dame in Paris, which was begun just a short time later, the vaulting already shows the Gothic form of reaching to the heavens.

The church is 130 meters long; its two aisles flank the nave whose vault is an already impressive 35 meters high. The sexpartite vault of the nave of Notre-Dame was completed in c. 1200.

In the late Gothic period rib vaulting developed into ever-more imaginative variations. In the different artistic landscapes regional phenomena emerged in which the rib, originally important to the con­struction, increasingly became a decorative element, and ultimately covered the surface of the vault as an entire network of ribs. Decorative types of rib in stellar, net and fan vaulting evolved in England and Germany in particular. The development of a vault structure divided into small sections can be seen in the Lady Chapel of Gloucester Cathedral, for example. This apsidal chapel was completed around 1500 and displays a richly decorated vault—a network of ribs with stone bosses set at their intersecting points. The Renaissance saw a return to barrel vaulting in church architecture. In addition this period brought a new flourishing of dome building, beginning with the construction of the dome in Florence.