Written in Stone
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by Catherine Carlisle
A special element of our Fall 2024 Study Trip Abroad to Tuscany and Extension to Emilia-Romagna permitted Decorative Arts Trust members a unique opportunity to witness the process behind an Italian Renaissance stonework practice that evolved from centuries of craft traditions, dating back to ancient Rome.
The Scarpelli Mosaici is a workshop in the heart of Florence where artisans have honed the skills of selecting, blending, and hand-cutting gems and stones to create extraordinary scenes in a technique known as “commesso Fiorentino” or “pietre dure,” which translates literally to “hard stone.” This form of mosaic reached the height of popularity during the High Renaissance (c. 1490–1527) in Florence and was derived from much older stone inlay techniques. The prolificacy of colorful stone decoration throughout Tuscany and Emilia-Romagna left us inspired by their beauty and awed by their intricacy.
Pietre dure involves creating images with cut stone. The process and final look are distinct from what is generally considered tile mosaic, in which similar-sized squares of stone, ceramic, or glass are cemented together. The two methods’ origins, however, are connected, and the techniques overlap in some architectural contexts. Floor, ceiling, and wall mosaics enriched Roman buildings from present-day Britain to Tunisia, but the technique was refined and became a major form of artistic expression in the early Christian era, particularly in Ravenna. The seat of the Western Roman Empire in the 5th century, and then of Byzantine Italy until the 8th century, Ravenna’s strategic location near the Adriatic Sea enabled extensive cultural exchange with Constantinople, as exemplified in its early Christian monuments with interiors decked in stunning mosaics.
The Mausoleum of Galla Placidia (figure 1), built c. 425 CE, is a particularly rich and surprising example. Its modest exterior belies a lavishly decorated interior with mosaics composed of tesserae depicting a variety of religious scenes against a field of vibrant blue. They are some of the best-preserved mosaics in the world. The period in which the mausoleum was built represents a shift in Ravenna’s rule from the Roman to the Byzantine Empire. Emperor Constantine adopted Christianity in 330 CE and moved his capital from Rome to Constantinople, at the eastern frontier of the Roman Empire. Early Christian churches, such as San Vitale in Ravenna (figure 2) or the Hagia Sophia in Constantinople, were built and decorated with mosaic imagery meant to evoke the heavenly realm and communicate the Bible to illiterate worshipers.
Tile mosaic techniques gained popularity alongside another decorative stonework application called “opus sectile,” in which floors and walls were inlaid with shaped pieces of stones (rather than squares) to create images. This method spread throughout Ancient Rome and Judea as slab floors came into use. Simple geometric and floral designs evolved into more elaborate compositions. The floor of the Duomo di Siena may be considered the apotheosis of the art form. Upon entering the cathedral, one is immediately struck by a profusion of colorful stonework. Massive columns of striped white and black marble mediate an elaborate painted ceiling and the spectacular marble floor. Nearly 14,000 square feet are covered in 56 panels depicting Biblical and philosophical imagery. Sienese artists supplied the designs for the floor in several stages between 1370 and 1550. Some of the earliest works employed a technique called graffito, in which lines are chiseled out of white marble and then filled with black stucco to create shading and outlines (figure 3). Later panels feature more complex designs and stones of varying colors (figure 4).
Naturally, it would seem, the Florentine art of pietre dure evolved from the ancient Roman opus sectile, with the process of intricately inlaying pieces of stone applied to domestic decorative arts instead of architecture. Marble inlay reached new levels of complexity in 16th-century Florence under the influence of the Medici family, whose patronage of the arts and humanism ushered in the Italian Renaissance, a period marked by a renewed interest in antiquity, including ancient Rome.
Creating pietre dure is a highly skilled process. Colored stones are sliced and cut to shape, with each stone precisely chosen for its color values in order to create shadows and dimension. The stones are assembled and inlaid onto a marble substrate, fitted together so precisely that the contact between each element is nearly invisible. Although the precision of the design holds the pieces tautly in place, they are further affixed to the substrate with a natural adhesive, typically beeswax and resin. The finished work is then hand polished and buffed to a shine.
Pietre dure scenes were integrated into furniture and other objects, often works that were for public display in a domestic setting. For the Medici, the stones used in pietre dure works were not only beautiful for their tone, but useful in what they symbolized. Cosimo I, Grand Duke of Tuscany, had a particular interest in archaeological marbles and hosted an atelier in the Palazzo Vecchio for the processing of precious stones. He even celebrated his conquest of Siena by re-erecting an ancient Roman column in the Piazza Santa Trinita in Florence. The column is topped with a statue of Justice carved out of porphyry, a stone symbolic of royalty in the ancient world. The use of certain stones expressed particular messages to the public and also affirmed the power of the rulers who funded such projects. Cosimo and his sons Francesco and Ferdinando invited stone engravers from all over Europe to work in Florence, resulting in a steady rise in the technical innovation of the more painterly pietre dure art form (see cover and figure 5).
In 1588, Ferdinando organized the artisans into workshops called the Galleria dei Lavori, originally located in the Uffizi. Artisans specialized in creating decorative objects to furnish grand ducal residences or as presents for foreign rulers. By the end of the century, Florence had gained an international reputation for the production of pietre dure works, and the diffusion of the art form through diplomatic gifts resulted in patrons elsewhere in Europe establishing their own workshops and enticing Italian artisans to train local craftsmen. For example, Louis XIV hired Florentine hardstone craftsmen to work at the Royal Gobelins manufactury in Paris, and Holy Roman Emperor Rudolph II brought entire families from Milan and Florence to Prague to create magnificent works for his Kunstkammer.
The Gallerie dei Lavori is today known as the Opificio delle Pietre Dure and operates as a museum and a laboratory dedicated to the preservation of pietre dure. The museum retraces the evolution of the practice through historic artworks, and also demonstrates the process and techniques to create masterpieces. However, many of the finest examples of Florentine pietre dure and works in precious stones are found today in the Palazzo Pitti, the largest of the Medici’s Florentine residences. The Palazzo’s collections span centuries of stone decoration artistry. A porphyry bust of Cosimo II by Mattias Ferucci (figure 6) dates to 1621, and an ebony prie-dieu made in 1620 (figure 7) features both a mosaic panel depicting the Baptism of Christ and a pietre dure panel depicting green-stemmed flowers in a lapis lazuli and gold vase. Lapis lazuli was a particularly prized stone for its rich blue color and was extracted from Badakhshan, now Afghanistan. Difficult to obtain and to carve, works in this stone express the wealth of the patron and skill of the artist. A 1583 flask carved out of a monolithic block of vibrant blue lapis lazuli and adorned with gold fixtures is found in the Palazzo’s sumptuous Summer Apartments.
The Table of the Muses (figure 8), dates to the 1830s and is considered a later masterpiece of the Galleria dei Lavori. A monumental work, it was started by Aristodemo Costoli and Giovan Battista but required many more craftsmen and over two decades to be fully realized. Today it occupies the center of the Castagnoli Room and greets visitors entering the Palatine Gallery.
In tracing the history of pietre dure and other stonework practices from the ancient Roman Empire through the Renaissance to today, we see the evolution of technical mastery and of cultural influence. Key historical sites, such as the Palazzo Pitti and the mosaics of Ravenna, provide context for understanding how Italian artisans adapted and expanded on earlier processes, transforming them into unique expressions of Renaissance ideals. Trust members left Tuscany and Emilia-Romagna awestruck and appreciative of these masterpieces in stone—whether adorning a cathedral floor, brightening a chapel’s dome, or displayed within the halls of a palace.
Catherine Carlisle is the Manager of Educational Programs at the Decorative Arts Trust.
A print version of this article was published in The Magazine of the Decorative Arts Trust, one of our most popular member benefits. Join today!