1.
THE MIRROR IMAGE
THE GATES OF THE BAPTISTERY
By the early 1400s the Baptistery of St. John at the heart of Florence was already ancient, its origins lost in the mists of time. According to Giovanni Villani, the city’s medieval chronicler, the structure was originally a Roman temple dedicated to Mars, the god of war. This seemed entirely appropriate to the proud Florentines, who believed their city had been founded by the rugged veterans of Julius Caesar’s legions. Modern archaeology has revealed that this was almost certainly not the case, and that the Church of St. John (or San Giovanni, as it was known) was built from the ground up as a Christian house of worship. Beyond this, however, experts are divided even to this day: Was the striking octagonal edifice built in the late fifth century, when the Church sought to extend its reign as the Roman Empire crumbled around it? Was it a monument to the conversion of the Lombards, the Germanic tribe that ruled over much of Italy in the seventh century? Or was it an expression of burgeoning civic pride when, in the eleventh century, the city of Florence emerged from centuries of obscurity to become a bustling hub of commerce and culture?1
We do not know, as the thick walls of the baptistery hold tight to their secrets. For a thousand years the walls bore witness as each and every Florentine newborn passed through their gates. In a soothing rhythm of Christian life, men and women, rich and poor, commoners and aristocrats of ancient lineage, all were baptized in the shadow of those walls and joined together in a community of the faithful. Other events were far less tranquil, as, generation after generation, the walls stood silently by while the violent civic life of an Italian city-state raged around them. Beginning around the dawn of the second millennium C.E., as Florence rose in power and wealth, life in the city swung wildly between years of peace and prosperity and periods of brutal strife and civil war. The ancient families of the countryside, who ruled Florence during the Dark Ages, battled for power with the wealthy merchants and bankers who increasingly came to dominate the city’s economic life. Rival clans of magnates turned their city dwellings into fortified towers and fought pitched battles in the streets, leading to the victory of some and the banishment of others. Guelphs, or champions of the Papacy, fought Ghibelines, who defended the rights of the German emperor, until the Ghibelines were finally driven out, never to return. And members of the working class, full-blooded Florentines who labored in the service of their wealthy brethren, rose up repeatedly to assert their political and economic rights. Wise to the danger, the squabbling clans of the city’s elite would put aside differences long enough to crush the popular uprisings and ensure that the “republic” would continue to be ruled by those rich in money or land.
But on one summery day, in about the year 1413, the ancient walls of the baptistery were treated to a scene unlike any they had witnessed before.2 It began unremarkably, as a short man in his mid-thirties, with a balding head and aquiline nose, marched briskly through the chill morning air and headed to the monumental doorway of the Duomo, across the piazza from the baptistery.
Known officially as the Cattedrale di Santa Maria del Fiore (Cathedral of St. Mary of the Flower), the Duomo was the pride of Florence—its main church and one of the largest and grandest in all of Christendom. Compared to the ancient and myth-shrouded baptistery, the Duomo was then practically new, a recent addition to the Florentine skyline and as yet an incomplete one. Nearly 120 years after its first stone was laid down, in 1296, the great cathedral was still missing its distinctive giant dome, so familiar to visitors today. Although it had been envisioned by the cathedral’s architects as a key element in their design, no dome on such a scale had ever been built, and its construction had so far exceeded the capabilities of the best master craftsmen of the day.
In due time the man walking past the baptistery that morning would change all that, for he was Filippo Brunelleschi (1377–1446), who would one day make his name as the designer and builder of the great dome. But on that day in 1413 Brunelleschi had other matters on his mind: he walked directly under the great archway of the Duomo’s main doorway as if he were about to enter, then abruptly turned around to face the baptistery. In his hand he held a modest painting, about one foot square, and a mirror of roughly the same size.
Anyone standing close to Brunelleschi that day in the shadow of the archway would have noted with surprise that the painting was not, as one might expect, a religious scene of the kind favored by the artists of the period. It was, rather, a simple depiction of the precise view from the spot where Brunelleschi was standing: the Baptistery of St. John as seen from the entrance to the Duomo, except that in the place where the sky would normally be the painting was coated with burnished silver, reflecting anything passing before it. Even more surprisingly, near the center of the painting, at the precise point depicting the baptistery’s wall opposite the cathedral’s doorway, there was a small hole. Brunelleschi raised the painting to his face and peered through the hole at the octagonal walls of the baptistery across the piazza. As puzzled onlookers watched, he raised the mirror and placed it in front of the painting, so that all he could see through the hole was the painting’s own reflection. What, they must have wondered, was he doing?
While Brunelleschi in 1413 had yet to acquire the towering stature he would reach in later years, he was, nonetheless, already a well-known figure in Florence. A master goldsmith by trade, young Filippo got his first chance to make his mark in 1401, when at twenty-four he was a leading contender in a competition to design a set of giant bronze doors for the baptistery.3 Brunelleschi’s entry, depicting the sacrifice of Isaac and his rescue by God’s angel, was fiercely expressive and impressed both the judges and the Florentine public. But he nevertheless lost the competition to the even younger craftsman Lorenzo Ghiberti (1378–1455), whose design was elegant and refined rather than dramatic.
The contrast between the two rivals extended beyond their artistic sensibilities. Ghiberti was not only a brilliant craftsman but also a sociable and amiable man with a penchant for quiet diplomacy. Throughout the competition he reached out to fellow artisans, consulted them, and incorporated their suggestions in his design. Brunelleschi, in contrast, had already earned a reputation as irascible, arrogant, and suspicious, a difficult man jealous of his methods and his credit. “To disclose too much of one’s inventions and achievements is one and the same thing as to give up the fruit of one’s ingenuity,” he told the engineer Mariano di Jacopo Taccola years later, and there is no doubt he practiced what he preached.4 He spent the year allotted for the competition working alone, in secrecy, never letting anyone but his closest companions see what he was doing. As a result, when the time came to pick the winner, Ghiberti had many friends among the judges and in the community at large, whereas the taciturn Brunelleschi was just as he liked it—alone.5
What happened next is much in dispute. Ghiberti, years later, claimed that he won the competition outright: “To me was conceded the palm of victory, by all the experts and by all those who had competed with me. Universally I was conceded the glory without exception.” Yet exception there surely was: according to Brunelleschi’s contemporary and biographer Antonio Manetti (1423–1497), when the time came to choose a winner the judges were already well familiar with Ghiberti’s panels, and could not believe any of his competitors could do better. Once they saw Brunelleschi’s striking design they realized their mistake, but felt unable to go back on what they had well-nigh announced—that Ghiberti was the clear winner. They settled on a compromise, declaring both men winners and commissioning them to work together. Ghiberti agreed; Brunelleschi, characteristically, refused, and walked away from the project, leaving the design and casting of the baptistery doors in his rival’s hands.6
THE SPELL OF THE ANCIENTS
Devastated by his loss in a competition he thought he deserved to win, Brunelleschi did not linger long in the shadow of his triumphant rival. Instead, he traveled to Rome, where he spent much of the next fifteen years far from the jealousies and rivalries of his native city. And if disappointment was enough to keep him away from the city on the Arno, it was something else that drew him inexorably to Rome: an obsession with for the ancient classical civilizations, which Brunelleschi shared with many of his most distinguished contemporaries.
This passion for ancient Greece and Rome had spawned a movement known as humanism, which had begun in the previous century but was now sweeping through Italy and reshaping the intellectual landscape.7 For the medieval schoolmen, ensconced in the famous European universities, the humanists had little but contempt. For all their learning, the schoolmen, in the humanists’ opinion, relied almost exclusively on a single ancient source, the writings of Aristotle, which they had by secondary (and, according to the humanists, corrupt) translation from Arabic. Even worse, the schoolmen’s very language, medieval Latin, was but a pale shadow of the rich and flowery language of Cicero and Livy. Little wonder that the schoolmen were obsessed with abstruse Aristotelian commentary and pointless theological debate. On the questions that the humanists believed truly mattered—how to live a good, moral, and worthy life—the medieval schoolmen were silent. There was nothing for the humanists but to make a clean break with their medieval forefathers and draw directly from the ancients.8
In their quest to recover ancient learning, the humanists studied philosophers such as Plato and Seneca, scientists such as Archimedes and Ptolemy, historians such as Polybius and Tacitus, and poets including Virgil and Ovid. But of all the ancient authors none was more greatly admired than the Roman statesman Marcus Tullius Cicero (106–43 B.C.E.), who embodied the humanist ideal to perfection. Cicero was not only the greatest of Roman orators, and a moral philosopher of note, but also a man who put his teachings to the test. A lifelong participant in Rome’s cutthroat politics, he saved the state from a dangerous conspiracy while serving as consul and was hailed by the Senate as Pater Patriae (“Father of the Country”). One could ask for no finer model of linguistic purity, literary prowess, and civic engagement.
FOR THE MOST PART, HUMANISM was a literary and philosophical movement focused on books and texts. Itinerant scholars such as Poggio Bracciolini traveled far and wide in an effort to locate lost ancient works that might be hidden away in the monastic libraries of Europe. Seeking out the most authentic versions, they worked hard to restore the texts to their pristine glory in their original tongues, mostly Greek and classical Latin, but also Hebrew, Arabic, and other languages. These newly recovered texts would then circulate among the humanists, replacing existing (and allegedly corrupt) medieval versions if such existed, or adding new ancient sources if they did not.
Brunelleschi, however, was not a literary scholar. A brilliant artist, architect, and engineer, he was not a man to spend his days poring over ancient manuscripts. For his humanist friends the passion for the ancients meant recovering the writings of Plato, Cicero, and Lucretius and returning them to their original brilliance. For the practical-minded Brunelleschi it meant something else: studying the physical traces of the ancients—the buildings, aqueducts, roads, and sculptures that they left behind. The humanists traveled to far-flung corners of Europe in pursuit of their original texts. Brunelleschi, in contrast, headed straight to the capital of the ancient world and the home of its greatest monuments: Rome.9
At the turn of the fifteenth century, Rome had sunk to one of the lowest points in its long and illustrious history. Back in the first century C.E., as the capital of a great empire, the city had boasted a population approaching two million, making it by far the largest city in the Mediterranean world, and probably anywhere. But four centuries later, with the empire in steep decline, the population had dwindled to less than half that number. The barbarian invasions that followed, accompanied by the collapse of commerce throughout Western Europe in the early Middle Ages, saw the city’s population crash to a tiny fraction of its ancient heights. Even the revival of urban life in the eleventh and twelfth centuries, which saw ancient towns come to life and new ones spring up throughout Italy, did little to improve the fortunes of Rome. While cities such as Florence and Venice grew into bustling centers of commerce and manufacture, the ancient imperial capital fell further and further behind. In time the popes of the Renaissance would rebuild and repopulate the city and make it a worthy capital of their spiritual empire. But in 1403, when Brunelleschi arrived, Rome was a poor and disease-ridden town of perhaps 30,000 souls, many of whom lived like vagabonds among the monumental ruins.
The young Florentine, however, had no interest in the sad, dilapidated Rome of his day. All he saw was the city’s past greatness: the remains of the great temples in the Forum; the seemingly indestructible roads, many still in use; the ruins of the massive aqueducts that had supplied water to the city of millions. Among the great structures still standing he surely would have noted the circular Colosseum, built by the emperors Vespasian and Titus in the first century C.E., and the monumental public baths built by the emperor Diocletian around 300 C.E., renowned for their high, vaulted ceilings. Most striking of all was the Pantheon, with its massive dome, whose span and height of 142 feet was still the largest in the world.
Brunelleschi, to be sure, did not come simply to admire the faded glory of the Eternal City: he was there to learn everything he could about the structures of ancient Rome, from simple abodes to great monuments, and to determine how they were built. As his biographer Vasari told it more than a century later, “his studies were so intense that his mind was capable of imagining how Rome once appeared even before the city fell into ruins.”10 If the humanists’ dream was to recover the intellectual world of Cicero, Seneca, and Tacitus, Brunelleschi’s was to recover their physical world—the streets they walked, the houses they inhabited, the temples in which they worshipped.
Rather than work alone, as was his habit, Brunelleschi this time was accompanied by a friend, the sculptor Donatello. Together the two Florentines set to work surveying every structure they could find: they “made rough drawings of almost all the buildings in Rome … with measurements of the widths and heights as far as they were able to ascertain,” Manetti tells us. Since the structures were in ruins, and the original street level was buried deep in the ground, this was easier said than done. It often proved necessary to dig up the structures’ foundations in order to determine their original shape and true height. When the job was too great for the two of them, they hired laborers, and when measuring heights and distances directly was impractical, they relied on geometrical measurement techniques, using surveying rods and mirrors. To record the measurements “they drew the elevations on strips of parchment graphs with numbers and symbols that Filippo alone understood.” And so they surveyed house after house, and ruin after ruin, over the entire ancient city.11
Day and night the two Florentines labored on their colossal undertaking, but no one in the city understood what they were up to with all this digging and measuring. Lacking a better explanation, the Romans assumed the two were looking for gold or marketable goods, and so they became known in the city as “the treasure hunters.” The Romans may not have been the only ones confused, since according to Manetti even Donatello was partly in the dark about Brunelleschi’s true purpose. Secretiveness was to Brunelleschi second nature, and, as far as was possible, he kept his ideas from even his closest companion.
What, then, was Brunelleschi hoping to accomplish with his exhaustive survey of Roman antiquities? One goal, undoubtedly, was a professional one: Brunelleschi wanted to learn the construction methods of the ancient Romans so that he could make use of them in his own projects. For example, according to Manetti, “he considered the methods of centering the vaults and other systems of support, how they could be dispensed with and what method had to be used, and when.”12 Perhaps he was already devising the machines that he would use, years later, to build the great dome of Florence’s cathedral.
But there was something more to Brunelleschi’s “treasure hunt” than the acquisition of technical knowledge. Brunelleschi believed that the ancient architects designed their structures in accordance with perfect mathematical harmonies, which were responsible not only for the soundness of the buildings, but also for their beauty. His goal, according to Manetti, was “to rediscover the fine and highly skilled method of building and the harmonious proportions of the ancients.”13 Some of these harmonies were fairly straightforward: the interior of the dome of the Pantheon was an almost perfect half-sphere, and the classic columns used in all public buildings were constructed according to strict mathematical proportions. Ionic columns were nine times as high as the diameter of their base, Corinthian columns ten times their base, and so on.
Other symmetries and harmonies, however, could not be so easily discerned. Brunelleschi believed that the buildings of Rome harbored many more secrets, which could be uncovered only through painstaking systematic work. By surveying, measuring, and recording the heights, lengths, shapes, and distances of every ancient structure in Rome, he was hoping to uncover those hidden mathematical harmonies that guided the ancient builders of the Eternal City and had since been lost. In the hills of Rome others might see a haphazard and disorderly jumble of ruins in various stages of disrepair. Brunelleschi saw the outlines of a perfect, harmonious order that pervaded every structure—and the entire city.
THE VIEW FROM THE DUOMO
Even while still spending most of his days as a Roman “treasure hunter,” Brunelleschi made regular visits to his native city, where he remained a familiar figure. And it was one of those visits, in or around 1413, on one morning when we find him walking briskly past the baptistery, site of painful memories, and toward the doors of the Duomo. He may well have been contemplating the great cathedral’s missing cupola, while nurturing a secret ambition that he would be the man to build it.
Yet the objects he was carrying that morning were not the tools of a goldsmith and caster of bronze, as one would expect of the master craftsman who had lost the competition for the baptistery’s doors by the slimmest of margins. Nor were they architectural designs or engineering plans, as later generations, who know him as the builder of “Il Cupolone,” might expect. A mirror and a painting with burnished silver and a hole in the middle are all that Brunelleschi held in his hand. In what must have been no more than a few hours, and using these simple objects, he forever transformed the way people perceive and experience the space around them.14
Here’s what Brunelleschi did: First, he held the back of the painting to his face, placing the hole in its center before his eye. Manetti, who held the painting in his hands decades later, reported that the hole was “as tiny as a lentil bean on the painted side” and that it “widened conically” on the back side, reaching “the circumference of a ducat.”15 Brunelleschi pressed his eye to the cone and looked through the hole toward the baptistery. With his other hand he held up the mirror in front of the painting so that, instead of the actual octagonal structure, he saw its image in the painting reflected back at him. There was the baptistery and the buildings around it as he had painted them. There was the blue-gray sky, the drifting clouds, and passing birds captured in the burnished silver on the painting and now reflected from the mirror and back at Brunelleschi’s eye. From the peephole at the center of the painting, Brunelleschi was looking straight at the painting’s reflection in the mirror. The artificial image was almost indistinguishable from the view of the actual baptistery as seen from the same spot.16
It was surely one of the most baffling scenes ever to take place before the ancient walls of the baptistery. From a distance it would have appeared that Brunelleschi was inexplicably covering his own face with the back of a painting; from close by, when the hole in the painting was revealed, it seemed that he was going to enormous lengths to see what was freely available to the naked eye—the octagonal outlines of the baptistery in the morning light. Why the painting, the peephole, the mirror, if the only purpose was to reproduce the exact scene that could be viewed without them? What, one might understandably wonder, was Brunelleschi up to?
The answer lies precisely in the bewildering identity of the natural view from the cathedral’s doorway and the artificial view of the painting and mirror that Brunelleschi worked hard to achieve. The whole purpose of the experiment, in fact, was to demonstrate that he had mastered the secret of the true representation of nature, one that differs not at all from the real thing. The more similar the mirror image of the baptistery—seen through the hole in the painting—is to the actual view from the Duomo’s doorway, the better. The best indication of the experiment’s success was if the mirror was suddenly yanked away, the view through the hole in the painting remained practically unchanged. Brunelleschi had succeeded in capturing a three-dimensional view of an object and then reproducing it from scratch on a flat canvas. Nothing like it had been accomplished before, but his contemporaries soon had a name for it: they called it perspective.17
That Brunelleschi was widely considered the founder of perspective we know from his contemporaries: not only his biographers, Manetti and Vasari, but also the humanist Domenico da Prato, who wrote admiringly about “the perspective expert, ingenious man, Filippo di Ser Brunellesco, remarkable for skill and fame.”18 And Manetti’s friend Cristoforo Landino reports that “the architect Brunelleschi was also very good at painting and sculpture; in particular, he understood perspective well, and some say he was either the inventor or rediscoverer of it.”19 Sadly, however, Brunelleschi’s painting of the baptistery is lost to us. Manetti, writing decades later, tells us that he had held it in his hands and “seen it many times,” and it was listed among the effects of Lorenzo the Magnificent, Medici ruler of Florence, after his death in 1492. But that is the last we hear of it, and as a result we cannot know with certainty what exactly Brunelleschi did in the painting to earn him his reputation as the founder of perspective. Yet his use of a mirror in his experiment provides an important clue.20
Introduced to Europe in the thirteenth century, mirrors were still rare and expensive items in Quattrocento Italy, the objects of widespread fascination. A mirror, after all, is a flat, two-dimensional surface, just like a wall or a painting. And yet when we look at a mirror it is almost impossible to maintain our awareness that the mirror is flat, because the perception of depth practically overwhelms us. We see our own reflection not on the surface of the mirror but behind it, just as we see all the objects around us deep in the mirror’s illusory space. Furthermore, all objects appear at the same distance “behind” the mirror as they are before the mirror’s surface.21
Today we take mirrors and their images so much for granted that we hardly think them worthy of comment. Yet there is magic here: without any human intervention, mirrors produce a perfect three-dimensional image on a flat surface, one that is practically indistinguishable from the original. How do they do it? And what does an artist, using all the skill and human artifice at his disposal, need to do to reproduce the effect? This seems to have been the question on Brunelleschi’s mind as he was designing his experiment. If he could reproduce a mirrorlike sense of depth in his painting of the baptistery, then the image the flat painting reflected back at the observer would appear not flat at all but three-dimensional. For an observer, it would be as if they were looking directly at the baptistery.
To experience firsthand how a mirror produces its depth effect, try a simple experiment: stand directly in front of a mirror at your home alongside at least two parallel objects perpendicular to the surface of the mirror. The traditional parallels are railway tracks or the sides of a road, but since you are unlikely to find these in your house, then towel or clothes racks, or the outlines of furniture or door frames, will do just as well. Using a digital camera, take a photograph of the image in the mirror, including yourself, the camera, and the various parallel objects. Then inspect the resulting picture, and with a ruler extend the lines of the parallel racks (or furniture, or door frames) until they intersect. You will find that all the lines meet exactly—but exactly!—at the point occupied in the picture by the lens of the camera. If we move the camera to a different location—higher or lower, left or right—and take the picture from there, the result will be exactly the same: the intersecting lines will follow the camera lens wherever it goes. In a mirror, it is fair to conclude, all parallel lines perpendicular to its surface meet at a single point—the one occupied by the observing lens.
Back in 1413 Brunelleschi did not have the benefit of cameras, digital or otherwise, but had to observe the image on a mirror directly. This is not easy to do, because looking at a mirror we are so powerfully drawn into its three-dimensional world that it is next to impossible to conceive of it as a flat surface. Yet Brunelleschi, making good use of his experience using mirrors in his Roman survey and translating structures into two-dimensional diagrams, apparently managed to do so: in a mirror, he discovered, all parallel lines meet at a single point. In his case, of course, the point was occupied not by an artificial camera lens but by the observer’s own human eye.
It was a remarkable discovery, and Brunelleschi clearly believed that it held the key to replicating the “mirror effect” in a work of art. If a painter, through his skill, could artificially reproduce what a mirror did naturally, then surely the surface of the painting would appear just as transparent and three-dimensional as the surface of a mirror. There is every reason to believe that that is precisely the effect Brunelleschi was aiming for when he painted the image of St. John’s baptistery as seen from the portico of the Duomo. In his painting the parallel sides of the portico where he was standing, the parallel rows of cobblestones on the pavement between the Duomo and baptistery, the parallel lines of the roofs at the edge of the piazza on both sides of the baptistery, all converged on a single point in the painting. It is what is known today as the vanishing point.
In a mirror the vanishing point is located at the observer’s eye as seen in the glass. In a painting, which usually does not include an image of the observer, the point is defined by the place where the observer “would have been” had the canvas been a mirror instead: it is an eye-level point on the canvas, directly across from where the observer should be standing before it. In the case of the baptistery painting, that is in the middle of the structure’s eastern doors, the ones facing the cathedral.22 By placing his peephole in this location, Brunelleschi was reproducing the precise effect he had observed in mirrors, where all parallel lines converged onto the observer’s eye. When he looked through the hole at a mirror held before him, the flat surface of the painting disappeared and was replaced by a deep three-dimensional image of the baptistery and the piazza. Without the vanishing point, a painting is like a wall—an opaque barrier to vision, hiding what lies behind it and replacing it with jottings on a flat surface. But the vanishing point transforms a painting into a window, which does not block our view but rather opens up an alternate reality behind it and invites us in.
FIGURE 4: Brunelleschi’s experiment
In Rome, Brunelleschi had spent years searching for the hidden geometrical principles that the ancients used to build their city. Years later he would make use of what he learned in his architectural work. The Church of San Lorenzo, for example, which he designed and began building simultaneously with the cathedral’s great dome, was constructed almost entirely of standard square units, combined in different proportions of whole numbers. Most famously, it was geometrical harmony that inspired the aesthetics of Il Cupolone, just as the geometrical principles of engineering ensured that the construction was possible and the dome structurally sound.23
In the perspective experiment Brunelleschi was expanding the reach of geometry even further. Here was a geometrical secret that was not simply a matter of human artifice, like the monuments of the Eternal City or the great dome: it existed in nature itself, and manifested itself in the reflections of mirrors. Brunelleschi did not invent the principles of perspective but merely revealed a natural geometrical order that was already there. It wasn’t simply that men could use geometry to create great and wondrous objects. Instead, Brunelleschi’s experiment suggested, the world around us is already imbued with geometrical patterns that we need only reveal. Nature itself is geometrical.
If the implications of Brunelleschi’s discovery had been perceived at the time, they could have shaken the foundations of his world. Ever since its invention two thousand years before, geometry had been praised for its logical rigor and admired as a model for attaining true knowledge. Plato, who lived in the fourth century B.C.E., considered it the ideal science and a model for men seeking a glimpse of the pure and rational world of the forms, which, he believed, were the only things that truly existed. When, a few decades after Plato’s death, geometry was systematized and codified by Euclid of Alexandria, it became the embodiment of absolute, unshakable truth.
This, however, did not mean that the world itself was geometrical! Far from it. Plato thought the physical world was a corrupt version of the rational beauty of the realm of the forms, and was therefore entirely unsuitable for geometry. The Christian Church, which dominated the intellectual world of the Middle Ages, agreed. As punishment for original sin, men live in a fallen world of falsehood and confusion, a world that would never conform to the rational dictates of geometry. Finally, Aristotle, the greatest intellectual authority in Western Christendom, believed that knowledge of the world should be acquired from experience, and he was highly skeptical as to whether such knowledge would conform to the rules of geometry. In the Middle Ages, broadly speaking, geometry was often praised and broadly admired; but the world itself was decidedly un-geometrical.
Brunelleschi’s discovery challenged all that: here was a geometrical secret hidden deep among nature’s inscrutable mysteries. Nature, it turned out, could indeed follow the rules of geometry, and if this was the case for perspective, was it not plausible that other geometrical secrets are as yet hidden and awaiting their discoverer? Despite the teachings of Aristotle and the Church, Brunelleschi’s discovery hinted that the natural world might indeed be perfectly geometrical. Underlying the boisterous chaos and variety that we see around us there may yet be a rational order, which humans can comprehend and even imitate. It is hard to say how Brunelleschi himself perceived his discovery. It may have been, to him, no more than a clever trick that artists might use to dazzle clients and spectators. But the potential implications of the discovery were immeasurably greater, and over time they would upend Europeans’ entire understanding of their world.
In the immediate aftermath, few paid much attention to Filippo’s strange trials in the Piazza del Duomo. Shortly after the trial at the baptistery, Brunelleschi produced another perspectival painting of the neighboring Piazza della Signoria, apparently using a more complex method that included oblique vanishing points.24 But that seemed to be the end of the matter, and apart from Domenico da Prato’s reference to him as the “perspective expert,” many years pass before we hear any more about it. It was only a decade later, in the 1420s, that paintings using Brunelleschi’s method began adorning the churches of Florence.
The man most responsible for introducing and disseminating the principles of linear perspective was the painter Tommaso di Ser Giovanni di Simone, universally known as Masaccio (1401–1428). A full generation Brunelleschi’s junior, he met the great architect in the early 1420s, when Filippo was the most powerful artist-engineer in Florence and Masaccio was a young painter from the provinces trying to make his way in the great city. The two formed a bond and, according to Vasari, Brunelleschi “worked very hard for a long time to teach Masaccio many of the techniques of perspective and architecture.” In 1423, likely at his mentor’s urging, Masaccio traveled to Rome, just as Brunelleschi himself had done two decades before. It was in the few short years between his return to Florence and his death at the age of twenty-seven that he produced the paintings that would establish him as one of the greatest artists of the Renaissance.25
THE INVENTION OF “INNER SPACE”
In 1425 the Dominican friars of Florence commissioned a fresco from Masaccio for their church of Santa Maria Novella, where the work, known as The Holy Trinity, can still be seen today. The main themes of the mural are no different from those of many medieval church paintings and would have been familiar to good Christians everywhere. At the center of the painting is Christ on the cross, set up in a hall with a barrel-shaped vault supported by columns, and flanked on either side by the Virgin Mary and John the Baptist. Above the cross looms God the Father, looking fixedly at the viewer and supporting the cross with his hands. Below the hall, and seemingly below ground, a skeleton lies atop a stone sarcophagus. The message was easily understood by members of the congregation, steeped as they were in the teachings of the Church: Christ transcends the certainty of death, and through his suffering extends a promise of eternal life.
But it is not the theological lesson or the main figures that make the painting so strikingly different from any that had come before it. It is, rather, the hall aboveground and the sepulcher below, the very space that the figures inhabit. In creating this space Masaccio followed Brunelleschi’s method so closely that the painting almost appears to be a formal exercise in linear perspective. Most strikingly to the viewer, the barrel vault extends directly from the surface “into” the painting and is divided into identical squares laid out in regular parallel rows. Following Brunelleschi’s guidelines, the parallels formed by the squares all meet at a single point, below the base of the cross. And similarly (if less obviously), the parallel sides of the subterranean sarcophagus also meet at the same vanishing point. Just as in the baptistery experiment, Masaccio positioned the vanishing point at eye level, about five feet and nine inches above the floor. The churchgoer at Santa Maria Novella is in precisely the same position as Brunelleschi was when he looked across the Piazza del Duomo at a point in the center of the baptistery doors. In the Trinity Masaccio had reproduced the mirror effect his teacher had tried to replicate years before. As in a mirror, the space of the painting, of the vault and the sepulcher, becomes an extension of our own space and sucks us into its imaginary world.
FIGURE 5: Masaccio, The Holy Trinity (ca. 1425)
Unlike any work of art before it, the Trinity makes explicit use of Brunelleschi’s principles, thereby creating a three-dimensional space within the painting.26 Yet, innovative as Masaccio’s technique was, there is no denying that the overall effect is static and rigid. The figures, while clearly inhabiting precise positions within the painting’s inner space, also seem as stationary and immovable as the columns around them, and not at all like living, breathing human beings. It would be two more years before Masaccio managed to produce lively and dynamic paintings that nevertheless fully adhered to the geometrical principles of perspective.
FIGURE 6: Masaccio, The Tribute Money (ca. 1427)
Around 1427 Masaccio executed a cycle of frescoes for the Brancacci chapel in the church of Santa Maria del Carmine in Florence, devoted to the life of St. Peter. The most famous of these is The Tribute Money, depicting how Jesus sent Peter to pluck a fish from the water and present the coin he would find in its mouth to the tax collector. Here again Brunelleschi’s principles are dutifully followed, but with a far lighter touch than in the Trinity. In place of the all-encompassing vault, The Tribute Money uses only a single structure on the right side of the composition to define the vanishing point. In place of the rows of squares that dominate the Trinity, here there are only a few short parallel lines of the balcony and the floor, just enough to produce the illusion of depth, but no more. In addition Masaccio seems to have mastered a principle that was implicit in Brunelleschi’s method: that the heads of the scene’s protagonists (and any objects at eye level), regardless of their apparent distance, should all be at the same height in the painting—that of the vanishing point.27
FIGURE 7: Lorenzo Monaco, Adoration of the Magi (1420–1422)
The result is a painting that has long been recognized as one of the masterpieces of the early Renaissance. Instead of forcing a geometrical straitjacket on the composition, the rules of perspective do just enough to bring the disparate elements into an elegant and harmonious whole. Linear perspective here is not an imposition on the painting but a resource ingeniously used to hold the overall composition together. In the two years between 1425 and 1427 Masaccio had transformed himself from a student of linear perspective to its master.
It is instructive to compare The Tribute Money with a work by a different Florentine artist, Lorenzo Monaco: Adoration of the Magi, painted only a few years earlier. The composition of Monaco’s painting is as striking as that of Masaccio’s—the figures are as elegant, the emotions as powerful, and the message as clear. Both paintings foreground the central narrative and position the main figures alongside an architectural structure, and in both the background is taken up with a forbidding mountainscape. And yet the overall effect is strikingly different: the swarm of figures in the Adoration crowd the surface of the painting and the forbidding mountain in the back serves as a final backstop that excludes any further extension of the painting’s inner space. In fact, the painting’s space exists only inasmuch as it is occupied by people and objects, and even the small areas of sky are sealed off with impenetrable gold.
In contrast, Jesus and his disciples in The Tribute Money fully inhabit the interior of the painting, whose depth extends into the distance, along the water and into the sky. Space here exists in itself, regardless of whether the figures and structures inhabit it or not. It is an absolute space established by the universal laws of geometry, and it precedes anything that takes place within it, even the miracles of Christ and the apostles. Only a few short years separate Lorenzo Monaco’s Adoration of the Magi from Masaccio’s The Tribute Money, and yet the two paintings seem to exist in different worlds. In the universe of the Adoration things are perceived in an imprecise jumble, much as they are in daily life, their location determined by their positions relative to one another. In the world of The Tribute Money all objects are precisely located within a preexisting space that extends to infinity. Monaco’s world was as it had been for his medieval predecessors—tactile, rich, and sensuous. But Masaccio’s world was different from anything that came before him: it was geometrical through and through.