THE CLASSICAL ORDERS

For many centuries in Ancient Greece temples were the most important form of architecture. They were, after all, houses built for the gods. Gradually the temple form of a square central space surrounded by columns came to predominate. Even the most fa­mous Greek temple, the Parthenon on the Acropolis, follows this model.

When the Parthenon was built in the fifth century B.C., Athens was the political and economic center of Greece and this temple, dedi­cated to the goddess protector of the city, Athena, took on a suitably monumental form. We can only imagine today how the Temple of Athena was richly decorated with architectural sculpture, and how sculptures and relief friezes adorned its facades. The cult image, a huge statue of Athena, was located in the central space, the cella. The roof of the temple -was supported by a whole row of columns, and the entire temple was made of white marble. Eight stone columns adorned the west-facing front of the structure, with seventeen pillars on each of the long sides. On these massive columns lay horizontal beams and, in turn, on top of these was the temple's pediment. A central aim of the architect was to create a harmonious relationship between the vertical lines of the columns and the horizontal lines of the entablature above.

As in the Parthenon, columns in Greek architecture were used as supports for a horizontal entablature. They were also used not only as an architectural element, a use that refers back ultimately to the tree-trunk that was used as a support, but they were also used for their own qualities, to lend order to architecture. To do this the Greeks developed three different types of column that can be distinguished by their three sections: the base, the shaft, and most clearly by the capital that finishes the column at the top. Another element was the beams that were placed horizontally on top of the columns and that led to the pediment. The appearance of these architectural elements and what their relative proportions should be determined the classical orders as they developed in Ancient Greece. With the establishment of these three architectural forms the Greeks created an architectural principle that architects followed until well into the nineteenth century. The plainest of the three orders is the Doric, named for the Ancient Greek tribe, the Dorians. This order was used in the building of the Parthenon. Its power­ful columns have no base of their own, but stand directly on the floor of the temple. The shaft of the column tapers towards the top and is articulated with vertical grooves, called fluting. At the top the shaft bulges out to be finished off with a covering slab, the abacus. Above the abacus are decorated lintels, and finally the pediment . The Ionic order originated in Asia Minor. Here the column has its own base, above which a series of bulges and grooves lead to a similarly fluted shaft. The top end of the column, the capital, is rolled up on both sides into the shape of snail-shells. These volutes give the Ionic column its characteristic of ostentation. The Ionic entablature is more lightly and delicately decorated than the Doric. The last of the three classical orders is the Corin­thian. The base, shaft, and also the entablature are similar to the Ionic order, except that the capital is an individual development: it grows out of a garland of leaves that then turn into volutes. This Corinthian variant of the capital, adorned with leaves and buds, re-appeared in Gothic architecture. Before that, however, the columns of the Corinthian order were adopted by Ancient Rome in particular.

The Romans adopted the classical orders as defined by the Greek architects. In the first century B.C. the Roman author Vitruvius set out their principles in writing in his ten-volume architectural work, De architectura. Here he describes Greek temples and establishes the proportions that relate column to entablature in each case. Roman temples demon­strate how the architects of Ancient Rome appro­priated the Greek formal language. Unlike Greek architecture, however, the columns built by Roman architects supported arches, not horizontal beams. The Colosseum, which was begun in 72 A.D., shows how the ancient classical orders persisted into the Roman period: from the outside the stories of the amphitheater are not only horizontal, but articul­ated in axes.

Arches supported by columns extend around the facade of the building. The three lower stories are built following the traditions of the classical orders most closely. On the ground floor plain Doric capitals top off the shafts of the columns, while, above them, Ionic capitals are used, character­ized by their rolled-up corners. On the third story Corinthian capitals created using plant forms are employed. While developments in the different orders took place even during the Greek period, it was, however, the Romans who were the first to create hybrid forms. They combined the Ionic with the Corinthian variations and thus added another form to the scheme: the Composite order. In the same way, it is only in Roman architecture that we find examples of the Tuscan order: here the shaft of the column is usually left smooth, but in all other respects the column is similar to the Doric variation.

With the rediscovery of the cultural riches of Anti­quity during the Renaissance, the classical orders too reappeared. Still extant buildings from the Roman period, such as the Colosseum, for example, made the study of the orders possible. At the same time Re­naissance architects started to look once again at the writings of Vitruvius. Architectural theorists were the first to pay them any attention. Leon Battista Alberti (1404-72), the embodiment of the Renais­sance idea of the universal man not only as a theo-retician but also as an architect, sculptor and poet, drew extensively on the architecture of Antiquity. Alberti studied the buildings of Rome and Vitruvius's treatise on architecture, bringing the ideas of art into Antiquity to his own era. In his 1452 work, De re aedificatoria [On the Art of Building in Ten Books] he produced his own definition of the three classical orders, which led to a great deal of interest. The architect Donate Bramante (1444-1514) was the first to try to realize his ideas. The Tempietto of S. Pietro in Montorio, Rome, which Bramante built in 1500 boasted a thorough-going Doric order.

The round temple is enclosed by a peristyle supporting a balustrade, and the center of the building is surmounted by a dome. In building this little temple Bramante drew on models from Antiquity, thus promoting a concept of architecture which had enormous influence on his contemporaries both within the architectural world and beyond. Bramante himself included the three orders in his numerous sketches for churches in Rome, not the least of which was the interior of St. Peter's Basilica, for which he chose the Corinthian order. This reversion to Antiquity became the accepted thing, and in the sixteenth century whole hosts of architects applied the classical orders to churches, villas, and palaces. Even the villa architect of the sixteenth century, Andrea Palladio (1508-80), frequently referred back to the classical orders in his buildings. Palladio created the entrance to his Villa Rotonda, which he built near Vicenza in 1566, as a temple frontage from Antiquity with six Ionic columns and a triangular pediment.

In the second of his Four Books of Architecture Palladio explained his use of this element: "In all the buildings for farms and also for some of those in the city I have built a tympanum [frontespicio] on the front facade..., because tympanums accentuate the entrance of the house and contribute greatly to the grandeur and magnificence of the building, thus making the front part more imposing than the others….”

Up until the era of Classicism in the eighteenth and nineteenth centuries the classical orders set the tone of the architectural canon in Europe. The Greek orders appeared once more in the context of city architecture with the Brandenburg Gate.

Berlin's last city gate, which has latterly become a symbol of German reunification, was created by Carl Gotthard Langhans (1732-1808) in the late eighteenth cen­tury. The architect made no secret of his passion for Greece, and in his sketch for the Brandenburg Gate he made reference to the design of the Propylaeum in Athens, the monumental gate on the Acropolis. In the Berlin version six Doric columns support the entablature, as well as the quadriga - Victoria, Roman goddess of victory, in her chariot pulled by four horses. In France too, classical architecture, and with it the classical orders, were very popular. In Paris, for example, Napoleon undertook to complete the unfinished Church of the Madeleine.

Now the building was conceived no longer as a church, but as a monument to the French army. Thus the temple form was chosen, which architect Pierre-Alexandre Vignon (1763-1828) carried out beginning in 1807. By the time the project was finished in 1842 the building had been returned to its original purpose, and the Church of the Madeleine became Napoleon's most important contribution to sacred architecture. The exterior is like a temple frontage from Antiquity with a continuous peristyle running around the entire building formed of richly decorated columns in the Corinthian order.

THE FIRST DOMES

Architects discovered thousands of years ago that they could enclose spaces not only with a flat ceiling, but also by using a semi-circular vault. This curved ceiling was suitable above all for centrally planned buildings, that is buildings which were planned on a round or square footprint. Domes were frequently used in Antiquity, and in Byzantine architecture they were part of a permanent formal vocabulary, being used primarily in mosques. At the end of the Middle Ages the vaulted form of the dome also experienced a renaissance, as demonstrated by the brilliant achievement of the dome of Florence Cathedral. However dome building had already reached its first peak 1,300 years earlier, in the Pantheon in Rome.

This temple dedicated to all the gods (in Latin pantheum means "to every god") is among the best preserved monuments of ancient Rome. The circular structure was built between 118 and 125 A.D. and remained in use as a Christian church even after the Roman period. A wide portico stands in front of the circular temple building and leads to the domed interior. The dome is as high as it is wide, and as the section shows, it was designed in the shape of a perfect sphere. The diameter of the rotunda is 43 meters, and this is the same as the height of the walls from the floor to the vertex of the dome. Light enters the interior through a round, nine-meter-wide opening in the center of the vault: this topmost oculus is the only source of light in the Pantheon. The dome is decorated on the inside with coffering: the five rows of sunken square panels reduce in size towards the oculus and intensify the effect of great height. The material of which the dome is made is a kind of lightweight concrete, to which a mortar of volcanic stones was added in order to reduce the net weight. The Pantheon in Rome is not only the largest dome in the ancient world but is also the largest dome to be created by being molded as a single unit.

Domes were of great importance in Byzantine architecture, as demonstrated by the Hagia Sophia, which was built in Constantinople ( now Istanbul) between 532 and 537. The capital of the Byzantine Empire was an important cultural and trade center in the early Middle Ages and the new Church of Holy Wisdom lived up to this status: for centuries the Hagia Sophia was by far the greatest church in Christendom. The ground-plan of the building is a unique invention, as in the Hagia Sophia it unites the longitudinally planned basilica with the centrally planned building. As such the church has an imposing vaulted roof, and an unsupported dome dominates the main space. The dome is almost 56 meters high and has a diameter of 31 meters. Further smaller domes complete the west and east sides of the building.

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The architects Anthemius of Tralles and Isidore of Miletus created a technical masterpiece in the construction of this dome. The main dome is sup­ported by pendentives, whereby an imaginary circle slices horizontally across the arches of the church and then a hemisphere is placed on this surface. The triangles which arise from the transition from square ground-plan to the circular form of the dome are known as pendentives. The ingenious dome con­struction of the Hagia Sophia collapsed, albeit only in part, as a result of an earthquake just a year after its inauguration. The impact on the dome had appar­ently shifted the pillars and load-bearing arches outwards. Reconstruction began immediately, and the new dome, now six meters higher, was already finished by 562. After the conquest of Constantinople by Sultan Mehmet II the Hagia Sophia, which had been both cathedral and the church of court and state, was converted into the most important mosque of the Ottoman Empire. This function is indicated by the four minarets, which still characterize the external appearance of the building. It is now used as a museum.

In the Middle Ages longitudinally planned buildings became more important than centrally planned ones, and so domes lagged behind by comparison with the groin-vaulted choirs, naves, and aisles of the great churches. During the Renaissance, however, cen­trally planned buildings were considered the epitome of symmetry and harmony and so monumental domes once again attracted the interest of architects. In this respect, the city of Florence and architect Filippo Brunelleschi (1377-1446) opened up a rich line of development. Building work on the Cathedral of Santa Maria del Fiore in the center of Florence had been in progress since 1296, but the vaulting of the dome still had to be completed.

The gigantic extent of the plan had already been sketched out: an eight-sided, fenestrated drum; the wall supporting the dome was over 41 meters in diameter and no less than 50 meters high. This cathedral dome was intended to outstrip that brilliant achievement of the ancient world, the dome of the Pantheon. Filippo Brunelleschi, who had won the competition to finish the dome, took on the task, beginning his spectacular feat of engineering in 1420. His solution for the future symbol of Florence was a double-shelled dome by means of which he achieved a new dimension in the art of vaulting . Together the inner shell, which is over two meters thick, and the thinner outer shell, along with the ribs which link them together, absorb the forces created by the dome. To let in light, the unsupported dome, like its Roman predecessor, is open at its vertex. Brunelleschi added a finishing touch to this oculus in the dome, the lantern. Constructing a vault over a building of this size presented the architect with a technical problem as well. It was not possible to erect supporting scaf­folding from the floor of the church because of the building's great height; and working with a cradle was too unsafe because of the huge diameter of the space. Brunelleschi also ventured into uncharted territory technically, designing a system by which the dome could be vaulted while supporting itself at the same time. The dome of Florence Cathedral heralded the beginning of a long analysis of the buildings of the ancient world, above all the Pantheon. The building of St. Peter's Basilica in Rome, for example, was another attempt to outdo the Pantheon and thus can be seen as emulating the dome of the cathedral in Florence.

Michelangelo began building the immense dome in the middle of the sixteenth century. In the event, he was unable to surpass the Pantheon dome in terms of its span, but succeeded in outdoing the ancient model by achieving a height of 136 meters. Michelangelo's dome for St. Peter's was a point of reference until well into the Baroque period, in particular in its impact from a distance: the dome which is visible from the outside is considerably higher than the dome built over the interior space. Domes appear in the most varied types of vault construction, and not only in Renaissance and Baroque churches. They also featured in residential buildings: Andrea Palladio (1508-80), the most sought-after villa architect of the Renaissance, also drew on the ancient temple form and introduced the dome into his designs for villas in the Veneto. Numerous palaces were adorned with domed rooms; and in the eighteenth and nineteenth centuries even government buildings acquired domes, for example the United States Capitol in Washington.

In the twentieth century, the invention of reinforced concrete introduced completely new possibilities for domed architecture as well. The range of concrete forms that were now available to architects was illustrated by Max Berg (1870-1947), for example, in his spectacular design for The Centennial Hall in Wroclaw, Poland (formerly known in German as Breslau), which the architect topped with a dome.

The large interior space of the Hall, which was completed in 1913 and was built to commemorate the uprising against Napoleon, consists of a vault 65 meters wide formed of reinforced concrete ribs. The 35 ribs come together like a star to form a ring, which is in turn surmounted by a small cupola. Around the four rings, which are stacked one on top of the other to create the dome, are continuous windows. Thus the construction of the dome remains visible, as broad, round arches form a continuation of the ribs and direct the structural forces into the foundations of the building.