In 1984 the Opificio delle Pietre Dure began to restore all the marble and bronze sculptures in the fourteen niches on the outside of the church of Orsanmichele in Florence; with this year’s restoration of Lorenzo Ghiberti’s bronze statue of Saint Matthew, the project is drawing to a close. Three of the newly restored statues by Verrocchio, Lorenzo Ghiberti and Nanni di Banco will soon travel to the United States and be exhibited at the National Gallery of Art.

A former grain market, Orsanmichele became a church in the fourteenth century, while preserving its civic vocation by becoming the religious center of the Arts [le Arti], the powerful crafts guilds which played a prominent role in the city’s politics and economy. Indeed, from the outside Orsanmichele looks more like a palazzo than a church. On the walls of its tall, crenellated, block like form are fourteen marble niches, originally assigned, starting in the Trecento, to house the patron saints of the various Arti. Facing outward, towards the city, and not half-hidden in shadows of a church interior, the effigies were supposed be a kind of public declaration of their devotion as well as the prestige of the Arti’s patronage – at the time, in Florence, power and wealth were expressed through art (o tempora, o mores…). This explains, therefore, how the extraordinary new path taken by Florentine sculpture in the Quattrocento led to the replacement of the “outdated” Gothic statues in the church’s niches with the humanized divinities carved by Donatello, Nanni di Banco, Ghiberti, and Verrocchio.

An exceptional “open air” museum of Renaissance statuary was thus created, as precious as it is vulnerable, given the increasingly noxious environmental conditions that have emerged in the last half century. A confirmation of this latter problem can be found by comparing photos of Donatello’s marble Saint Mark taken in the 1920s, when the statue was still nearly intact, with photos taken fifty years later, which show erosion from acid rain in the face and drapery. For this reason, in the 1980s the Opificio launched a program of overall review of the sculptural complex of Orsanmichele, beginning the restoration with none other than the Saint Mark, the most endangered of the statues, and supplementing their preliminary diagnostic inquiries with documentary research on the sculptural cycle’s history. Cross-referencing the findings gathered in the two areas of research has made it possible to ascertain that the marble statues’ particularly darkened surfaces were due not only to atmospheric deposits but also to an artificial patinating treatment of linseed oil pigmented with mineral soils [terre minerali], applied sometime around the late eighteenth or early nineteenth centuries.

In all likelihood this intentional modification of the statues’ appearance corresponded to demands of conservation as well as taste. The oil is a water-repellent that was often used in the past to waterproof and protect stone, and the artificial “bronzing” effect that the treatment gives to the marble sculptures made them fit in better with the bronzes with which they alternated in the niches, in keeping with a widespread preference in the eighteenth and nineteenth centuries for artificially “ageing” the surfaces of stone works and even paintings.

Once the nature and chronology of the treatment was verified for the Saint Mark as well as the other marbles later slated for restoration, it was decided to remove the patination, which betrayed the artists’ original intentions, obscuring, among other things, the remnants of the gilding, applied with gold leaf and glue, which once lit up the white shapes of the patron saints of the Arts with luminous glimmers. The severe solemnity of the Saint Mark’s forms was tempered with gold in the saint’s hair and flowing beard, as well as in his clothing’s embroidery and on the stud in the middle of the binding of the Gospel he is holding on the right. On the other side, Nanni di Banco’s gigantic Saint Philip once displayed its beardless face under a head of blond hair while a golden thread extended down his ample gown, highlighting its pleated edge. In the niche beside it, the four figures of the Santissimi Coronati, also by Nanni, have gold embroidery on their gowns, even over certain chisel-marks made to fit the statues inside the niches, a detail that has led one to believe that the gilding was applied after the statues were already in place, probably to heighten the effect of the overall view.

Only rare and precious fragments of this ancient sparkle remain today, made more legible by the latest restorations, which use a new laser technology that in cleaning can separate the deposits and patination from the underlying traces of gold. In being cleaned, the bronzes of Orsanmichele – whose constituent material is in a better state of conservation than the marble – have also recovered the softness and luminosity of the original metal forms, which likewise show traces of lacquer gilding. In the case of the three statues by Ghiberti, who rediscovered the art of monumental bronze casting, under the deposits that once hid it we can now see silver leaf inlaid into the bronze to suggest the corneas of the eyes, as in the sublime Greek statues of gods and heroes.

The Humanistic heroes appointed to protect the Arts in Florence could risk further damage from defenseless exposure to air pollution. The Opificio, along with various Florentine Soprintendenze, thus opted to place them within museums after their restoration, as a cautionary measure subject to reversal. Furthermore it was decided the originals would be replaced with copies which will preserve, in the original setting, an image and memory of the sculptures that have been an integral part of the city’s historic centre for over half a millennium.

The removal of the originals from their intended setting was made partly less traumatic by the decision to keep them at Orsanmichele, in the great hall on the floor above the church, which has been turned into a Museum for the statues formerly in the niches. Soon, when the Saint Matthew returns, the cycle will be complete again and visible in the renovated Museum, in whose vast space the statues lose none of their physical and psychological monumentality, offering themselves to our eyes in their entirety, as though they were still in the artists’ studios, awaiting to be placed in their setting. Let us hope that at some future time, wiser and more advanced than our own, they can be returned there.