Nero’s Golden House broke “the tyranny of the right angle.” Even the great courtyard in the center of the façade splayed out its flanks to make three sides of an irregular hexagon. The grounds of the Golden House, as we have seen, abounded in fantasy. The idea of a rural villa in the heart of Rome was itself fantastic. An artificial lake, on the low ground where the Colosseum would later stand, was surrounded by villages in the varieties of Greek classic architecture—a bizarre encyclopedic museum of the long Roman tradition of country villas.
Embedded in the center of the east wing, his octagonal hall with its circular canopy of concrete marked a new departure in architecture. It used man-made stone—Roman-improved concrete—to make almost any kind of shape. Here the vaults that had served the practical purposes of baths and of basilicas converged. The straight walls of an octagon merged into the smooth curves of a dome, creating a salon with a circular opening in the center. Fountains cascading down the rear completed the fluid spectacle. Interest now focused on the interior to create a new sense of closure. Light streaming down from the center and filtering between the columns that elevated the dome made this interior world newly autonomous. The elements of the Roman revolution in architecture were all there. Concrete-domed space now offered men interior heavens of their own creation and the domed interior, as we shall see, became a man-made New World.
The emperors who succeeded Nero were eager to relieve themselves of the odium of the expropriation that had provided the land for the palace, and they displaced Nero’s palace by monuments to their own generosity. Aided by the Roman fires of 80 and 104, they erased the traces of Nero’s megalomania. The low ground that Nero had made into an artificial lake to improve the vista from his palace became the site of the Colosseum (Flavian Amphitheater) for free public entertainment. On top of what had been the domestic wing of the Golden House, Trajan built grand public baths, where all could enter without charge. Under Domitian, Nero’s porticoes around the Forum became an elegant shopping center. Only seventy years after its construction, all that remained of Nero’s prodigious Golden House was the lonely 120-foot gilded statue of Nero. Legend reported that, after Nero, each emperor put the image of his head in place of Nero’s. Unfortunately, the powerful early popes did not follow this example, but simply destroyed the statue.
The secular emphasis of the Roman architecture was signaled in the very names they gave to their grandest works. The Greeks knew their monumental buildings by the names of the gods whom they honored—the Parthenon (after Parthenos, the virgin goddess, Athena), or the Temple of Olympian Zeus. But Romans knew their architectural monuments by the names of the emperors who had them built—Nero’s Domus Aurea, the Flavian Amphitheater (the Colosseum), Hadrian’s Pantheon, the Baths of Caracalla. Roman architects never attained the celebrity of architects in later ages and received little credit for their most famous Roman buildings. The principal architect of Nero’s Golden House was probably Severus, but we know little about him or the team of specialists he supervised, despite the radical novelty of the building he helped shape.
Romans had forgotten where the Golden House had stood when, in the fifteenth century, they dug under Trajan’s Baths and came upon rooms that had been part of Nero’s domestic wing. They could not explain these underground rooms painted in the Pompeiian style, and assumed that they were originally decorated grottoes. Later, Raphael, who had an intense interest in ancient Roman remains, had himself lowered down on ropes to study the “grottoes.” Raphael imitated the style of the “grotto” walls, in which fantastic forms of people and animals were intermingled with flowers, garlands, and arabesques into a symmetrical design, when he painted the Vatican loggias. This was called grottesche—in the style of the grottoes. “Grotesk,” William Aglionby’s English treatise on painting explained in 1686, “is properly the Painting that is found under Ground in the Ruines of Rome.” After Raphael (1483–1520), the word became popular for distorted, exaggerated, or humorous forms in painting or sculpture. And so today Nero’s bizarre ambitions survive secretly in our everyday language.
If Nero’s buildings were soon torn down, their example lived on. Twenty-five years after the Golden House, Domitian’s palace, benefiting from still further improvements in the quality of concrete, followed the Neronian example with domes and curves enlivening even the domestic wing. In another twenty-five years, the newly liberated architecture flowered in Hadrian’s villa, a curvesome world where people took for granted their gently shaping interiors.
14
Dome of the World
BY a lucky accident of history, the best-preserved monument of ancient Rome, the Pantheon, is the triumph of the Roman revolution in architecture. That triumph survives, too, within our daily sight—in churches and mosques and synagogues, in urban chapels and country seats, in the political capitals of monarchies, dictatorships, and democracies. The dome of Hadrian’s Pantheon lives on across the West, proclaiming the triumph of art over politics. Peoples who never knew the Roman Empire, nor ever were governed by Roman law, could not resist the grandeur of Roman architecture. The dome of the Pantheon has been imitated to exalt the God of the Hebrews, the Savior of Christians, the Allah of Muslims, and the Sovereignty of the People.
This versatility of the Pantheon style is no wonder, for it was a “canopied void.” A symbol of man’s ability to make space his own, Hadrian’s dome provided a man-made emptiness for every religion and every nation to fill in its own way. Here we see at the same time a plain symbol of man’s power, of the emptiness of that power and man’s impatience to fill that void with something of his creation.
When we visit the Pantheon today in Rome we find it hard to think of it as a triumph of prosaic and prudent organization. On the Campus Martius we see a vast domed cylinder fronted by a columned and pedimented porch in the familiar Greek style. As we pass through the porch, however, and enter the empty circular hall which is the Pantheon, we are overawed by its simple rotundity. This man-made world has as its own sky a coffered dome with its own light, through a large (twenty-seven feet in diameter) circular opening (or oculus) at the top. After the familiar solidity of the stone columns and flat ceilings of the entrance we are suddenly struck by the comprehensive openness of the interior. As the focused sun streams through the oculus, the building becomes a vast orrery, recording in the movement of sunlight the revolutions of the earth.
This triumph of what was most distinctly Roman in architecture was the creation of one of the most passionate Roman devotees of Greece, Hadrian (born 76; emperor 117–138). He actually did for the Greeks what they could never do for themselves when he formed a single Greek federation with headquarters in Athens. And he gave equal representation to all the Greek cities. He codified the Athenians’ laws, and completed their Temple of Olympian Zeus. Having rebuilt the shrines of Delphi, he was personally initiated into the mysteries at Eleusis. He assumed the title Olympius proclaiming a Grecophile Roman emperor who admired beauty everywhere.
The Golden House of Nero, the Pantheon of Hadrian, the Hagia Sophia of Justinian, the Abbé Suger’s St.-Denis, and more recently the Versailles of Louis XIV—all celebrate their inspirer and organizer rather than the technicians and professionals who designed and built them. The epoch-marking buildings have commonly fulfilled the vision of amateurs. These eponyms had the power and the will to do what expert builders and traditional craftsmen dared not.
Architecture, precisely because it is so collaborative, has opened opportunities for the amateur to try new stratagems, outrageous and expensive novelties. For centuries, only princes and popes and Maecenases could commission paintings and sculpture, could command marches, sonatas, and symphonies to be composed, could hire eulogies, epics, lyrics, and threnodies. But the designs themselves were the works of the artists. Pope Paul III could order Michelangelo to decorate the Sistine Chapel but could not design it. Architecture was different. Since the fulfillment required vast resources and the labor of many men, the sovereign could play th
e architect and create the design.
In the reign of Trajan, who preceded Hadrian, Apollodorus of Damascus (c.20–c.130?) was the emperor’s minister of works and chief engineer, designer of Trajan’s forum, concert hall, and baths, and of several triumphal arches. Trajan’s famous bridge across the Danube, which Apollodorus built, was the emperor’s proof that the Empire would not be bounded by a mere river. Here Trajan showed “that there might be no obstacle to his going against the barbarians beyond it.” The bridge itself became a symbol of the difference between the prudent Hadrian and his expansive predecessors. Hadrian destroyed the Danube bridge, fearing that it might help the barbarians to invade the Empire.
But in architecture Hadrian had the arrogance of the amateur. His own pretensions as an architect made the celebrated Apollodorus an irritant. Hadrian’s envy of the great architect-engineer of his age produced the legend that Hadrian banished and then executed Apollodorus. Historic encounters between Apollodorus and Hadrian were still being reported by Dio Cassius a century later. Once when Emperor Trajan was consulting Apollodorus, Hadrian interrupted with some comment. At the time, it seems, Hadrian had been making architectural drawings of his own. Then Apollodorus impatiently retorted to Hadrian, “Be off, and draw your pumpkins. You don’t understand any of these matters.” Hadrian could never forget the slight. Yet as emperor he still sought the eminent professional’s counsel. When Hadrian sent Apollodorus his own design for the Temple of Venus and Rome, he formally asked the architect’s opinion. Bluntly Apollodorus replied that the temple should have been built on higher ground to make it stand out more conspicuously on the Sacred Way. Within the temple itself, Apollodorus added, the statues had been made too tall for the height of the cella. “For now, if the goddesses wish to get up and go out, they will be unable to do so.” Hadrian was understandably vexed, not only to be criticized so freely, but especially because the mistakes by this time could not be corrected.
If Hadrian was no expert architect, he was an enthusiastic and tireless builder, a model of the cultivated ruler. The roster of Roman emperors lists megalomaniacs, paranoiacs, matricides, and wife murderers. But the list could dazzle us also with the philosophical, poetic, and architectural talents of Roman emperors who sought immortality in the arts. Of these none excelled Hadrian. “His nature,” the uncharitable Dio Cassius (155?–post 230) wrote, “was such that he was jealous not only of the living but also of the dead.” And, we might add even of the unborn, whom he was determined to impress.
Born in Rome in 76, Hadrian was only nine when his father died, and he was put in the care of his father’s cousin, the future emperor Trajan. In Trajan’s childless household, Hadrian was the emperor’s favorite; he married Trajan’s grandniece, and became the heir apparent. By the unusually early age of thirty, even while still fighting alongside Trajan in distant Dacia, he was made praetor. After the whimsical oscillations of court favor, Trajan formally adopted Hadrian as his successor just before his death in 117.
As emperor, Hadrian aimed to consolidate rather than extend the Empire. He traveled all across the Roman world from Britain to Palestine enforcing discipline and fortifying borders. In an age when absence from Rome was an invitation to rebellion by ambitious rivals, Hadrian showed self-confidence by his extended travels. Ruthless execution of his enemies, which he regularly blamed on others, helped him hold power for more than twenty years.
Monuments of Hadrian’s ambitions, whims, enthusiasms, and prejudices were spread across the Empire. In northern Britain his great stone wall from Wallsend-on-Tyne to Bowness-on-Solway held the frontier against the barbarians. On one of his travels in Asia Minor he fell in love with a handsome youth named Antinoüs (born c.110) and made him his companion. When Antinoüs drowned in the Nile in 130 there were rumors that he had sacrificed himself for some mysterious purpose. To assuage the emperor’s grief, cults of Antinoüs sprang up across the Empire, and statues of Antinoüs became familiar. A city in Egypt was christened Antinoöpolis.
In the early 130s Hadrian had ordered a ban on circumcision, probably because of his horror of physical mutilation. He had made castration a crime equal to murder. But he ignored the sacred significance of circumcision for the Jews. In 134, protesting Hadrian’s prohibition of their ritual, the Jews of Judaea, led by Bar Kokhba, rose in revolt. Then Hadrian’s officers dissolved Judaea, which became Syria Palaestina under a consular legate and two Roman legions. In this way Hadrian made the Jews a “homeless” people, and created the Jewish Diaspora.
“The explorer of everything interesting” (omnium curiositatum explorator) was Tertullian’s (160?–230?) praise of Hadrian. He showed his administrative talents in codifying the praetor’s edicts to make the laws more certain, and in humanizing the treatment of slaves. Hadrian’s creative spirit was best expressed in architecture. The remains of his villa at Tivoli sixteen miles northeast of Rome still charm the tourist. The original country palace, stretching a full mile, displayed his experimental fantasy. There, on the shores of artificial lakes and on gently rolling hills groups of buildings celebrated Hadrian’s travels in the styles of famous cities he had visited with replicas of the best he had seen. The versatile charms of the Roman baths complemented ample guest quarters, libraries, terraces, shops, museums, casinos, meeting rooms, and endless garden walks. There were three theaters, a stadium, an academy, and some large buildings whose functions we still cannot fathom. Here was a country version of Nero’s Golden House.
Tivoli’s historic significance is less in its grandeur than in its wonderfully relaxed way of shaping the relics of the right-angled Greek masses into curves and vaults and domes. The emperor’s circular island retreat, the Teatro Marittimo, enclosed concave and convex chambers. Tivoli displayed every conceivable form of arch and undulation. There were temples to assorted gods, including one to the Greek-Egyptian god Serapis. The vestibule of the Piazza d’Oro was covered by a curious pumpkin vault, of the design that had excited Apollodorus’ ridicule. The new architecture of interiors revealed itself too in the outward shapes. The exterior of the Piazza d’Oro expressed the curved interior, which was the heart of the building. The architecture of mass was being displaced by an architecture of space, no longer piling and hewing stone for the outside viewer, but creating a novel world within.
Hadrian’s Pantheon in the heart of Rome, like Nero’s renewal of the city, was another example of how catastrophe sparks creativity. For, like the Parthenon, it was not the first public building on its site. There Marcus Agrippa (64?–17? B.C.), friend of Augustus, had built an earlier Pantheon, which was destroyed by the fire of 80. Rebuilt by Domitian, it was again destroyed by fire in 110. This gave Hadrian his opportunity.
In his new Pantheon, Hadrian would exploit all the possibilities of concrete with bold design and engineering technology. Astonishingly his building still stands for us to see. It stands because, having been consecrated as a church, it was cared for through the ages. But it must be experienced from within. It was perhaps the first great ancient monument designed as an interior. In its dazzling burnished void we are overwhelmed by the challenging circular emptiness of a rotunda 150 feet (43.3 meters) across and of precisely the same height. The natural light pouring through a circular open skylight reminds us that the natural world is still out there. Eight piers mark semicircular chambers serving as niches. But our eyes are carried upward to the coffered dome.
Modern architects are awed by the ingenuity that used an intricate scheme of concrete brick-reinforced arches to overarch so vast an opening and for eighteen hundred years bore the concrete dome’s enormous weight. What made this possible was artificial stone shaped to order in the very place where it would be used. This first required a forest of timbers, beams, and struts to provide the hemispherical dome of wood on which the concrete could be poured. Concrete comprised nine tenths of the whole building. Brick only gave body and strength to the concrete and carried down the thrust of the weight. Marble facings and mosaic fragments were just veneer.
Concrete, too, was at the very foundation where it provided a solid deep ring on which the whole rested. For the rotunda walls concrete had been poured into trenches of a thin brick shell. As each layer dried, another brick shell was provided to make a trench for more concrete. And so it went until the terrace level from which the dome curved inward. At this point the timbers provided a wooden dome on which to pour the concrete. And negative wooden molds had been prepared to impress the shapes of the receding coffers.
The Romans had mastered some surprising subtleties with their rough raw material. Their concrete always included an “aggregate” of broken rocks. While these fragments, heavier than the matrix of lime and pozzolana and sand, increased the mass of the concrete and its supporting capacity, they also increased the weight. The higher up one went in the structure, the less need there was to support weight and the more desirable that the material itself should have less weight. A close study of the concrete used in the rising levels of the Pantheon shows an astonishing subtle variation. The weight of aggregate used in the concrete decreases in regular layers upward in the building. The heaviest chunks of aggregate are in the foundations, and then they become lighter in the lower walls. The aggregate in the concrete of the topmost part of the dome is fragments of pumice, one of the lightest of volcanic rocks.
The idea of an intricate wooden frame large and strong enough to support the concrete cast for the Pantheon dome staggered the medieval imagination. So they created a plausible legendary alternative. Was it not possible instead that Hadrian’s engineers had heaped up inside the rising Pantheon walls an enormous rounded mound of earth on which the cement dome could be cast? Of course this posed a new problem of how to clear the earth from the finished cylinder once the cement had dried. For this too they conjectured a solution. The shrewd Hadrian, they suggested, had the foresight to seed the earth with pieces of gold as the mound was built, and so left an automatic incentive for workers clearing the mound when the concrete vault had hardened in place.
The Creators: A History of Heroes of the Imagination Page 17