Digital Twins and Cultural Heritage Preservation
Digital cultural heritage preservation in digital art history and digital humanities study has only recently come into being. Moreover, with digital twin technology developing only recently and being applied to cultural heritage, scholarship is still in a nascent stage (Hutson & Olsen, 2022a). The recent developments began in 2001 with the digitizing of cultural heritage sites. Both ancient and modern sites were created, though access and use was often restricted to researchers and institutions. Such virtual environments (VE) were first developed using CAVE technology, as seen in the Foundation of the Hellenic World (FHW). Digital reconstructions were possible through the use of the technology, beginning Miletus, an Athenian and later a Roman colony on the coast of Asia Minor (Tzortzaki, 2001). The potential was recognized for museums and other cultural heritage institutions almost immediately. For instance, Roussou (2001), published on how the technology would be ideally suited for exhibitions in museums “edutainment.” Heading the call, many museums began integrating extended reality (XR) experiences in the first decade of the twenty-first century, including The Museum of Pure Form and The Virtual Museum of Sculpture (Loscos et al., 2004). These experiences were designed for use by the general public, who had no experience using this new technology. And unlike experiences for the scientific and medical communities, which tended to be longer, these were necessarily short to keep visitors moving through exhibition spaces (Carrozzino & Bergamasco, 2010). These site-specific XR experiences quickly gave way to completely virtual museums, such as The Exploratorium, a public science museum, and The CREATE project, an EU funded project that allows users to reconstruct archeological sites (Hutson & Olsen, 2022b). Around the same time, whole museum collections were digitized for viewing using augmented reality (AR) devices or head-mounted displays (HMD). Beginning in 2006, the Center for the Art of East Asia in the Department of Art History, Division of Humanities, at the University of Chicago (CAEA) started digitizing and archiving their collections of East Asian paintings and sculptures. Such examples of cultural heritage institutions to expand access to art-historical resources is driving digital twins today. The digitized collection at CAEA and others move the experience from a physical museum to a completely virtual learning environment (VLE) (Christou, 2010). The development is made possible through the recent availability of user-friendly interfaces and immersive design, coupled with shorter engagement duration, and has led to the design of VLE currently popular.
However, only in the last decade has the use of VLE to deliver cultural heritage content become widely available. Most notably this has been accomplished through the creation of computer-generated museums using 3D models or through digitization efforts of real museum spaces. A watershed moment occurred with the launch of Google’s Arts & Culture in 2011, which allowed virtual visits to museums, accessible to anyone with a smartphone. The company seized upon the democratizing potential of the technology with Google Cardboard in 2014, an inexpensive HMD that was quickly adopted for secondary education (Boel et al., 2021). Similar VLEs have been developed to tour real or virtual museums (VM), such as the Rijksmuseum, Amsterdam, and the National Archeological Museum of Marche in Ancona, Gyeongju VR Museum, South Korea (Favro, 2006; Clini et al., 2018). The Louvre also recently (2021) released their digital collection of over 480,000 pieces from its collections and made them available via their proprietary platform. One of the most impactful projects as of late has been overseen by UNESCO (2017–2020) and saw the creation of full virtual tours of World Cultural Heritage Sites (El-Said & Aziz, 2022).
Since the pandemic, the use of digital twins for cultural heritage as greatly expanded and adoption is seen across the globe in many areas. For instance, Bevilacqua et al. (2022) described different examples of VR applied in the cultural heritage, including a digital twin of the First Italian Parliament, which no longer exists. The reconstruction that used digital modeling and a prototype in VR was made available to visitors to Palazzo Carignano, Turin. Another example provided describes the creation of a digital twin of the Charterhouse of Pisa in Calci. The virtual environment created includes a reconstruction in three dimensions of frescoes and the cloister in various historical phases. As with the examples provided by UNSESCO, the creation of such digital twins may be driven by tourism, but has also opened a new avenue for researchers around the globe (Shahzad et al., 2022; Zhao, Guo, & Li, 2022).
While these digital twins provide examples of the processes used by European scholars to recreate and/or reconstitute architecture, another case study presented by Tan et al. (2022) demonstrate processes used in Asia. The study focuses on Xiegong, a unique element of Chinese historic buildings that is representative of the development of Dougong. The sense of urgency in the field of archeology, and relevent for our study, relates to the erosion rate and loss of the physical properties that need to be captured for posterity. Using 3D surveying technology, researchers reproduced a three-dimensional digital twin of the site in order to record and survey heritage buildings. In order to support the process, the researchers developed a methodology that aligns digital twin technology and the chronology of forms. Their approach included oblique photogrammetry, LiDAR, and building information modeling (BIM) to assist in archeological research into Xiegong. Xuanluo Hall in Sichuan, China was used as an example for the study and verified the usefulness of the approach with geometry and semantics. The results of the process confirms the viability of using digital twin technology to assist in the archeological research. Other studies confirm the viability for archeological research and preserving deteriorating structures (Rosa, 2022; Wang et al., 2022). Taken together, the processes used by research teams above in creating digital twins requires multiple areas of expertise and collaboration between technicians and scholars in order to create usable prototyptes for digital cultural heritage sites.
Chiesa dei SS Apostoli e Biagio
The Chiesa dei SS Apostoli e Biagio (Fig. 1), known to the English-speaking community that it serves as the Church of Santi Apostoli, is located in the heart of historic Florence near the Ponte Vecchio. The church is situated in the Piazza del Limbo, named for a cemetery previously onsite where unbaptized children were buried (Trotta, 1992), and, although being steps from the heavily trafficked path along the Arno River, is rarely visited aside from local parishioners. Likewise, despite the historical and religious significance of the church, there is suprisingly little published on it. The brief treatments of Busignani and Bencini (1979) and Trotta (1992) provide a brief history of the construction of the church, which began in the eleventh century, and descriptions of the artworks in the various side chapels. Baccio d’Agnolo (1462–1543) added a small campanile in the sixteenth century and Benedetto da Rovezzano (1474–1552) added a central Renaissance portal in 1512 with flat pilasters in white and gray marble flanked by the Altoviti coat of arms (rampant wolf) (Fig. 2) (Wellen, 2022). Finally, the church was restored between 1930 and 1938 (Trotta, 1992). Given that, arguably, the most famous aspect of the church is Vasari’s Immaculate Conception (1541), the 2001 treatment (AA.VV) of the church provides a summary of the history of the building and further insight into the restoration of the altarpiece. The most recent and useful treatment of the church was published in 2004 by Bertani & Trotta, which provides additional insight into the history of the construction of the church, information regarding the Altoviti family, who patronized rennovations, and the description of the artworks.
The Romanesque church begun in 1075 is dedicated to the Holy Apostles and St. Biagio, a fourth century physician, and bishop of Sebastea, Armenia (now Sivas, eastern Turkey). According to his hagiography, the saint was martyred on February 3, 319 CE, and is popularly venerated saints in both the Catholic and the Orthodox Church (Weatherwax, 2003). The dedication of the church to San Biagio occurred much later in the eighteenth century when the Grand Dukes of Lorraine suppressed many religious buildings, among them the church dedicated to this saint, not far from SS. Apostles. The latter, therefore, also received the title of the suppressed church and was from that time dedicated to SS. Apostoli and San Biagio (Busignani & Bencini, 1979; Lipp, 2022).
The church can be understood as a microcosm of Florence itself, both historically and culturally. Local legends surrounding the beloved church include ties to the ancient Romans, Charlemagne, the second "Wall" of the city, the Crusades, Michelangelo, and Leonardo da Vinci’s Mona Lisa. According to legend, the church is one of the oldest in Florence and was founded by Charlemagne in the ninth century (AA.VV, 2001). The assertion is clearly communicated in a carved plaque on the exterior façade (Fig. 3). The Romanesque façade (Fig. 1) with irregular masonry is retained on the exterior, as are many of the original architectural elements inspired by ancient Roman buildings on the interior (Fig. 4). The plan (Fig. 5) retains elements of Roman basilica design with a nave and two aisles with a semicircular apse. The green marble columns (Fig. 6), which were quarried from Prato, were spolia from the first century BCE ancient Roman baths near the Piazza del Limbo (Busignani and Bencini, 1979; Maxson, 2023).
The church has gone through many phases of construction and remodeling since 1075, when construction began. For instance, the ornately decorated, hand painted trusses of the wooden ceiling (Fig. 7), reminiscent of early Christian basilicas like Old St. Peter’s in Rome, was added in 1333 (Spieser, 2022). Details such as the floor mosaic is maintained from the original from the eleventh century and later restored with contributions from Florentine families like the Acciaioli, Altoviti, and Del Bene (Trotta, 1992). Unfortunately, only fragments remain because tombstones of these families (Fig. 8) were placed in areas throughout the church, starting in the thirteenth century, and this required destroying much of the original floor decorations. The floor is constructed with cocciopesto (mortar with brick, lime and sand) and some elements of the original decoration remain (Lancaster, 2021). In particular there is a marble-encrusted “tile” (formella), with animal representation, found during the restorations of 1930-38 (Bertani & Trotta, 2004). The style of the tile has similarities with those of San Miniato and the Baptistery. The apse area has maintained a Romanesque appearance, with undecorated stones visible (Bossi & Guidobaldi, 2015).
Although remodeled in the fifteenth- and sixteenth centuries, the structure is one of the few in Florence to retain its medieval architectural features and decorations. The primary patrons for the renovations and new construction were the Altoviti, another Italian banking family like the Medici who were papal bankers. Of the family, only Oddo Altoviti (1457–1514) is named in the records associated with the fifteenth-century construction efforts as he was the commissioner of the tomb in the left aisle (Fig. 9), which he had made for himself and his brother Antonio Altoviti (1454–1507) by the sculptor Benedetto da Rovezzano, who also carved the holy water font (Bertani & Trotta, 2004; Petrucci, 2021). His date of birth would contradict the reported information that an Oddo Altoviti would marry Giovanna Gherardini (whose niece would be Lisa Gherardini, identified as the model for Leonardo da Vinci’s Mona Lisa) in 1432 (unless there is another Oddo) (Trotta, 1992; Soranzo, 2022). Antonio's sons, including the famous Bindo, and those of his brother named Stoldo, Bindino and Antonio, were also patrons for the church (Rowland, 2021). For example, Bindo will be the commissioner of the chapel dedicated to the Immaculate Conception with the panel painted by Vasari. Local tradition holds that Michelangelo himself convinced Bindo Altoviti (1491–1557) not to raise the ground level of the church as he had planned and instead to preserve the original Romanesque floor. While Bindo had befriended Michelangelo, the claim cannot be substantiated in the historical records (AA.VV, 2001).
The revitalization of the church included construction of new side chapels in the sixteenth century begun under Oddo Altoviti (1457–1514) in the fifteenth century. The first to be built were the five on the left aisle (Fig. 10) (now four because the first one was demolished during the restorations of 1929-30). In 1431, there were already two chapels under the patronage of the Altoviti family, the second on the left aisle and the one at the end of the right aisle. These chapels are decorated with altarpieces, including the Adoration of the Shepherds flanked by Saint Andrew and Archangel Raphael and Tobias by Maso di San Friano (1536–1571) (Fig. 11); the Archangel Saint Michael and Lucifer altarpiece by Alessandro del Barbiere (1538/43-1592) (Fig. 12) also created in the sixteenth century; and the Madonna and Child by Paolo Schiavo (1397–1478) (Fig. 13) from the original façade with fragments of the original fresco flanked by the preserved in sinopia preparatory drawing, early fifteenth century (Brookes, 1965; Bertani & Trotta, 2004; Borghini, 2007).
The same chapel holds an inset niche with a thirteenth-century reliquary created by Florentine goldsmiths out of bronze supported by a gilded copper cup from the fourteenth century (Fig. 14) that reputedly holds three flints known as the “Stones of the Holy Sepulcher” (Pietre del Santo Sepolcro). These two flints were believed to light the lamps of Christ’s burial tomb in Jerusalem and are reputed to have been brought back to Florence in 1101 by Pazzino dei Pazzi. The crusader was believed to have been among the first Christians to lead the way to the capture of Jeruslaem by scaling the walls of the city in the First Crusade (Addona, 2022). As such, the Pazzi adopted the flaming cup as an element of their coat of arms (Busignani and Bencini, 1979). Annual ecclesiastical celebrations continue to center the Church of Santi Apostoli in Florentine identity and this relic plays an important role. The aptly named “Fire Holder” is linked to the ceremony of Lo Scoppio del Carro (“explosion of the cart”) and the lighting of fireworks from the Portafuoco after Easter Mass in the Florentine Duomo each year. The “holy fire” produced when the flints are struck on Eastertide was carried throughout the city by young men bearing torches until the end of the fifteenth century. At that time, the tradition evolved to modern practice whereby a cart carrying an enormous candle is lit at Santi Apostoli and rolled throughout the city to the cathedral where fireworks are then lit in celebration (Langston, 2012).
In contrast, the five chapels on the right of the entrance (Fig. 6) were built beginning in the 1470s. The chapels are decorated with works from sixteenth century artists, including Giorgio Vasari (1511–1574). His Allegory of the Immaculate Conception (1541) is the centerpiece and one of the most celebrated works in the church and represents the Tree of Original Sin of Adam and Eve. Old Testament prophets surround the tree in the lower register and Lucifer is wrapped around the tree as the Virgin is elevated above, supported by angels. Bindo Altoviti commissioned the work for his chapel dedicated to the Immaculate Conception (O’Connor, 2000). The patron was later buried inside the church as well (1570) and his funerary monument (Fig. 16) above the door of the sacristy was executed by the Ammannati workshop. supervised by Bartolomeo Ammannati (1511–1592). The decorative cenotaph has two coats of arms of the Altoviti family with allegorical figures of Charity framed by a classical temple front with paired ionic flat pilasters surmounted by a pediment (Sorrentino, 2022).
The Bindo Altoviti tomb is directly across the apse from that commissioned for Oddo Altoviti (already mentioned), which is perpendicular to the Eucharistic Tabernacle (ca.1512) (Fig. 17) by Andrea della Robbia (1435–1525) and Giovanni della Robbia (1469–1529). The ceramicists created the glazed terracotta tabernacle to represent two angels pulling back a curtain to reveal the Annunciation inside a classical, barrel vaulted interior with seraphim in the spandrels and running horizontally in the entablature surmounted by the Holy Trinity and four flying putti above, who also carry garlands of leaves and fruit (Callahan & Cooper, 2010). Below the tabernacle, the Tomb of Donato Acciaiuli (1429–1478) can be seen in the fragments that remain of the Madonna and Saint John the Evangelist in two relief marble tiles from the Florentine School in 1333 (Ganz, 1982). Next to the tomb in the apse can be found the Funerary Monument of Antonio Altoviti (1521–1573) (Fig. 18), archbishop of Florence. Giovanni Antonio Dosio created the monument in 1547 with Battista Caccini carving the two busts above the side doors that flank the monument, which depict Charlemagne and Antonio Altoviti (Davis, 1976; Fehl, 1976; Dow, 2014).
The funerary monuments surround the high altarpiece and focal point of the church from the nave. The altarpiece of an Enthroned Virgin and Saints (Fig. 19) was painted by Jacopo di Cione (1325–1390) and Niccolò di Pietro Gerini (1340–1414) in 1382 and was originally located in the convent of the Poor Clares in via dei Malcontenti (Pope-Hennessy, 1949; Spring & Grout, 2002; Davies, 2009). The altarpiece was moved to the church in 1950 and replaced an altarpiece representing Pentecost. The work is situated behind the main altar in white and green marble created in a neo-Romanesque style in 1901 (Bizzarro, 2019). The Madonna and Child are flanked by two angels and Sts. Clare and Catherine of Alexandria. In the four gothic pinnacles atop the scene are Sts. Peter and Paul flanking an Annunciation scene. The panels to either side of the Madonna and Child represent Sts. Lawrence, John the Baptist, Francis and Stephen. The predella depicts the Three Kings in the procession of saints assembling to the right and left of a Nativity scene. The altarpiece is but one piece of the historical tapestry that makes up the church. In all, Santi Apostoli is a microcosm of the city of Florence and deserves greater scholarly attention. The prestige of the family and consequently the patronage of the church lasted until 1583 and in 1594 their bank in Rome went bankrupt. Thereafter, the church remained a hidden gem in the heart of the city (Bertani & Trotta, 2004).