Buon Frescoes

The restoration of Piero della Francesca's Legend of the True Cross cycle refocuses attention on one of the great lights of the early Renaissance.

A bearded man is sleeping in a tent, guarded by two soldiers, while a pensive youth sits at his bedside. From above swoops an angel, holding in his outstretched hand a small cross and heralding a flood of light that illuminates the pink conical top and yellow curtains of the tent. Like so much of the work of Piero della Francesca, the image is both profoundly still and mysteriously moving. The light has the sort of dramatic panache that we associate with Caravaggio and De la Tour, but unlike the light of those later masters, Piero's is so unearthly that we could easily imagine its source to be divine.

Constantine's Vision forms a part of one of the great fresco cycles of the Italian Renaissance, the Legend of the True Cross, which Piero painted in the mid-15th century in the Church of San Francesco, in the Tuscan town of Arezzo. For almost a decade these magnificent frescoes have been hidden, undergoing a restoration that was concluded in April. When the scaffolding came down there were a few surprises for devotees of Piero's masterpiece. "The greatest result was the recovery of the light of the frescoes," Silvano Lazzeri, the chief restorer, told me. "Piero is called the poet of light, but the light was hidden." Once the layers of grime were removed, you could clearly see the stars in the sky of Constantine's Vision. You also realized for the first time that the angelic light was falling not on a pitch-black night but on a sky that was just beginning to be suffused by dawn. As the work of a religious painter, that makes perfect sense. On the morning that follows this dream, the Roman emperor Constantine the Great will win a crucial battle and then, crediting the victory to Christ, he will embrace Christianity as the state religion.

Piero was devoutly religious and coolly rational. In his day those impulses did not seem contradictory. He studied mathematics—writing three surviving treatises, on perspective (the earliest known) and introductory algebra and geometry—as a way of gaining insight into the Creator's plan. His brand of religion is so cerebral and unsentimental that, in our own day, people often forget his subject matter and focus on the composition. "It's hard to fall in love with Raphael," says Marilyn Aronberg Lavin, an art historian and Piero specialist who lives in Princeton, New Jersey. "He seems at first too sentimental and full of pathos, insisting on ideas no longer universally believed. But you can love Piero in spite of his subject matter. The resurrected Christ, for example, is a figure of power, deeply moving whether you're a Christian, Muslim, or Jew. If form and design is what you want, he's your man."

Little is certain about Piero's life. He was born in Sansepolcro, near Arezzo, around 1412 and, except for a sojourn to Rome starting in the late 1450s, he rarely ventured far from Tuscany. Most of what we know about him is the work he left behind—and, until relatively recently, his painting had been forgotten. Piero fell out of fashion within 70 years of his death in 1492. "He was considered old-fashioned, archaic, stiff," Lavin explains. His published writings on perspective continued to be very influential, but his paintings were covered with sheets and ignored. Not anymore. To contemporary artists, Piero seems proleptically modern. In the San Francesco frescoes, there is a cityscape of Arezzo in the background of one scene that eerily—and beautifully—anticipates the work of Cézanne and de Chirico. And if Cézanne can be considered the father of Cubism, the Piero of those geometrically ordered rooftops could be seen as Cubism's grandfather. Even the muted blues and browns in Piero's palette remind one of the colors of Cézanne. Looked at in a different way, the monumental stillness and stately placement of Piero's figures suggest the work of another Post-Impressionist, Seurat. But there seems to be no end to what artists can derive from this painter who has been dead for more than 500 years. The ingenious games that Piero plays with perspective—the way in which he places figures at different distances and in front of or behind half-drawn curtains and pillared balustrades—greatly inspired David Hockney at the outset of his career.

While it is easy to enjoy and learn from Piero without any knowledge of his subject matter, a little background helps. The Arezzo frescoes illustrate a legend that had been current for at least two centuries before they were painted. Traversing the Old and New Testaments, the Legend of the True Cross traces the origin of the cross on which Jesus perished to a tree that grew on the spot where Adam died. The tree was later cut down for timber to construct a palace for King Solomon, who had to have the planks removed because they were magically shifting shape. On her famous visit to his court, the Queen of Sheba identified the wood and told him that a greater king than he would one day hang on it. Solomon nervously ordered the wood buried in a pool, but it wouldn't sink.

The legend then jumps forward in time to 200 years after Jesus' death. The wood from all three of the crosses of the Crucifixion was discovered by Helena, the mother of Constantine. She identified the True Cross and brought it to Jerusalem. (The battle that precipitated Constantine's conversion bears a thematic, if not narrative, connection to the legend, and so was typically included in any depiction, as it was here by Piero.) The final chapter is set some three centuries later. A king with a taste for sorcery hears of the Cross and steals it from Jerusalem. Outraged, the Byzantine emperor Heraclius defeats him and recovers it.

Commissioned by the wealthy Bacci family for the Franciscan friars (whose patron saint was said to have expelled demons from Arezzo), Piero's frescoes were painted on three levels in the chancel of the church. The more you look at the frescoes, the more you marvel at Piero's sophisticated counterpoint of form and content. The image of the messenger bearing the cross in Constantine's dream appears opposite an Annunciation, in which the angel Gabriel informs Mary of her destiny. The grandiose structure with Corinthian columns in which Solomon has his audience with the Queen of Sheba is reflected, on the facing wall, by the urban setting (including, in the background, the proto-Cubist Arezzo) where Helena identifies the Cross. As I scrutinized the paintings I kept seeing, or imagining, additional nuances that Piero included. The central window of the Renaissance facade that Piero has painted in the scene of Helena identifying the Cross is divided into small circular panes, just like the Gothic window in the real-life San Francesco chancel. The red laces on a warrior's breeches echo the blood coursing in rivulets from a victim's neck. The woodgrain of the pine Cross being toted by a laborer forms a halo around his head. I had the feeling that if I were to look indefinitely, I would continue to make new discoveries.

Discoveries of another sort were made by the team of specialists who conducted the restoration. Underwritten for $2.5 million by the Banca Popolare dell'Etruria e del Lazio, the restoration was urgently needed to correct the deteriorating condition of the frescoes. There were problems as far back as the 15th century, and the passage of time has only exacerbated them. "Because the church was built on medieval remains, the foundation was on an embankment," Lazzeri explained. "This caused the church to sink over the years, which was one cause of the damage to the frescoes. Another cause was the construction of the campanile, because the bell tower leaned on the right chapel." The tower was built soon after the painting of the frescoes; and indeed, the lunette on the top of the right side, depicting the death of Adam, has crumbled more than most, and the Victory of Constantine, at the bottom of the right side, is also badly damaged. "Another important event was water infiltration coming from the ceiling and penetrating the wall, causing the washing away of painted plaster," Lazzeri continued in a sad litany that began to resemble the story of Job. Perhaps worst of all, he said, was the modern plague of pollution, which caused a chemical process known as sulfation that ate away at the painted plaster.

There had been previous restorations, and unfortunately they only added to the problems. Cement was plugged in to stabilize the structure. Fixatives were applied to resist humidity. However, the fixatives trapped moisture in the wall, where it combined with salts in the cement to leach away, blister, and exfoliate the frescoes. "We removed the old fixatives used in previous restoration attempts, so that the wall could breathe," Lazzeri said.

The restoration has led to unexpected discoveries about Piero's techniques. Before beginning their work, the restorers conducted a six-year study, from 1985 to 1991, which included an examination of the paintings under ultraviolet light. Classic buon fresco, which is applied directly to wet plaster, shines violet-blue in UV light. However, almost half of the surface of the San Francesco frescoes beamed a fluorescent yellow, indicating that Piero had painted with tempera, in which the pigment is bound either with egg and animal glue (tempera) or egg yolk (tempera grassa) on dried plaster. By taking small samples, the researchers established that there was no dust between the original plaster and the tempera—in other words, the tempera had been applied almost immediately after the plaster dried and was therefore part of Piero's original conception. "Because there is a treatment for buon fresco and another treatment for the tempera, it was the most complicated part of all the restoration," Lazzeri explained. Seen purely in art-historical terms, the research revealed that Piero freely improvised from traditional buon fresco techniques to achieve his desired effects. According to Lazzeri, he used tempera to intensify the blue of his skies, the pink of his dresses, the red of his blood.

In a somewhat controversial decision, the restorers have chosen to cover the concrete intrusions of previous restorations with an application of plaster and paint, recreating stippled hillsides, expanses of sky, and decorative borders. However, they have limited their work to portions of the frescoes that are relatively easy to patch in. "Only the countryside, not the faces," Lazzeri observed. He pointed out the scene in which the Queen of Sheba kneels before the wood of the Cross, in front of Solomon's huge columned audience hall. The hills and edge of sky had been brown concrete fill; now they have been restored to what seems to be their original color. "Thanks to the restoration, you can perceive the perspective of the columns," he said.

After Lazzeri left I continued to compare the frescoes with photos that had been made before this latest restoration. In the battle of Heraclius, I was struck by the image of a large eye that had appeared in a spot that was covered by concrete, and which seemed to be floating in a field of brown. I looked and looked and couldn't place it in context. With me was a representative of the Banca Popolare. When I asked her, she suggested that it was a horse—and sure enough, when I reexamined it, I could see that the field of brown was the horse's neck. I thought it was odd that an eye—which was considerably more particular than a mountain or a cloud—should have been painted over what had been concrete. Later, in a trade-fair booth sponsored by the bank, I saw a pile of publicity material and, perhaps in a state of Quattrocento euphoria, I had a flash of recognition. The symbol of the Banca Popolare dell'Etruria e del Lazio is a wide-open eye. By placing an eye in Piero's fresco, the restorers were doing what the Renaissance masters themselves did so often, when they portrayed a pious couple in contemporary garb kneeling before the holy figures. To commemorate the generous contribution, they had included in the scene a representation of the donor.

The "Legend of the True Cross" can be visited daily in the Church of San Francesco. Reservations, which are required, can be made by phone (39-06-32-810) or in person (at the Piazza San Francesco). For more information, visit the Web site at www.pierodellafrancesca.it.