3D printing of scale models of the apostles’ statues from the Ark of St. Augustine (versione Italiana)

The Ark of St. Augustine, a marble monument that contains the sarcophagus with the remains of the saint, shows the statues of the twelve apostles on its long front and rear sides. A scale reproduction of the twelve statues (height of approximately 28.5 cm each, with solid exterior walls and empty inside) has been 3D printed in 2023, in collaboration with the Bulgarian Academy of Sciences (BAS) and with the financial contribution of the Association Piccolo Chiostro San Mauro ODV. These reproductions have been made from the 3D models realized by the students of the Computer Vision course of the Master’s degree in Computer Engineering of the University of Pavia under the supervision of prof. Virginio Cantoni during the academic years 2017/18, 2018/19, and 2019/20.
A plastic 3D printing material has been used. Nikolay Stoimenov of the BAS Institute of Information and Communication Technologies in Sofia handled the 3D editing for printer adaption and post-processing. The reproductions were painted by Roberto Gandolfi of the University of Pavia’s Department of Electrical, Computer, and Biomedical Engineering, and adhesive papers were used for detailing of the parchments. The project has been coordinated by Alessandra Setti of the University of Pavia’s Department of Electrical, Computer, and Biomedical Engineering.

The Ark of St. Augustine. The Ark, created in 1362 by unidentified craftsmen, is a magnificent example of Gothic sculpture crafted from white marble and preserved on the high altar of the Basilica of San Pietro in Ciel d’Oro in Pavia. With depictions of almost 400 people, plants, objects, animals, and schematic cityscapes, it is made up of 95 sculptures and 50 bas-reliefs. The total measurements are 307 x 168 x 393 cm. There are four layers, or orders, organized vertically, that make up the overall marble complex. The first order, from below, contains the sarcophagus and features the statues of the apostles alternated with those of evangelists, saints and virtues. In the second order, statues of saints, popes, and bishops are arranged in columns above the sarcophagus, while inside there is the statue of St. Augustine, lying on a sheet supported by six deacons, with an open book in his hands, surrounded by Doctors of the Church. The sculpture of the Redeemer and eight cords made up of seraphim heads are located in this middle section’s vaulted ceiling, creating compartments filled with bas-reliefs depicting saints, the archangels Raphael and Michael, and the Virgin Mary. The bas-reliefs of the third order represent the saint’s life in nine episodes, with his miracles are depicted in ten triangular tympana alternated with statues of angelic figures at the top, in the fourth order.

The 3D model of the Ark of St. Augustine. Under the direction of Prof. Virginio Cantoni, 105 students from the Computer Vision course made the 3D model of the complete artwork.

The statues of the apostles. The first order of the Ark depicts the fundamentals and role models of earthly Christian life. The statues of some of the key figures in the history of Christianity, starting with the apostles, are scattered among the statues of virtues resting on columns that also develop in the upper levels of the Ark. The names etched on the base of each statue, albeit not very legibly, and their customary symbols serve as means of identifying the apostles. Every statue carries a parchment that sequentially recite a verse from the Creed. The figures of Peter, John, James the Elder, Andrew, Thomas, and Bartholomew are depicted on the long front side, while Philip, Matthew, James the Younger, Simon, Thaddeus, and Matthias are represented on the long rear side.
Deborah Tandurella with her Bachelor’s thesis work in Electronic Engineering and Computer Science integrated the 3D models of the first-order items.

  Front side of the Ark. Starting from the front side, from left to right, the first apostle represented is Peter (3D model of Letebrhan Alemayoh, Anitta Antony, Gabriele Mirando, Riccardo Previtali), who with his left hand holds the keys to Paradise, ancient Christian symbolism of the universal Church. The first pope of the Catholic Church, bishop of Rome, where he was crucified under the emperor Nero, he holds a parchment that reads: “S. Petrus dixit: credo in unum deum patrem omni potentem creatorem caeli et terrae”. The second apostle, represented with his symbol, the eagle, is John (3D model of Letebrhan Alemayoh, Anitta Antony, Giulia Braghini, Nicole Cardili, Bhutani Yatin), the youngest, one of the evangelists and the “beloved disciple” who outlived the other apostles. He was the only one to die of natural causes. His parchment shows the fragment of the Creed: “S. Iohannes dixit: Et in Jesum Christum Filium eius unicum Dominu(m) nostru(m)”. The third is James the Elder (3D model of Letebrhan Alemayoh, Bianca Amiotti, Anitta Antony, David Feng), son of Zebedee, the first to be martyred. His parchment states: “S. Iacobus Zebedei dixit: Qui conceptus est de Spiritu Sancto, natus ex Maria Virgine”. The fourth is Andrew (3D model of Letebrhan Alemayoh, Bianca Amiotti, Anitta Antony, David Feng), brother of Peter, who, as written in the New Testament, was martyred by crucifixion. His parchment reads: “S. Andreas dixit: Passus sub Pontio Pilato, crucifixus, mortuus et sepultus”. The fifth is Thomas (3D model of Letebrhan Alemayoh, Anitta Antony, Zheng Wanyi), the skeptic who refused to believe without direct personal experience, but who later declared his faith and, according to tradition, spent twenty years of mission in India where he was martyred, near Madras, in 72 AD. His parchment reads: “S. Tomas dixit: Descendit ad inferos”. The last apostle represented on the front side is Bartholomew (3D model of Letebrhan Alemayoh, Anitta Antony, Matteo Di Gaetano, Francesco Giudice), one of the witnesses of the Ascension. His parchment reads: “S. Bartolomeus dixit: Tertia die resurrexit a mortuis”.

  Rear side of the Ark. The rear side shows the other six apostles: from left to right, the first one is Philip (3D model of Lorenzo Bonati), who was sent with Bartholomew to preach in Greece, Syria and Phrygia, where they were crucified upside down. Philip is commonly associated with the symbol of the Latin cross. His left hand is placed on his chest, while his right hand is holding a parchment stating: “S. Filippus dixit: Ascendit ad c(a)elos, sedet ad dexteram Dei Patris omnipotentis”. The second apostle is Matthew (3D model of Hossein Darab), one of the four evangelists, originally a tax collector. According to Church tradition, he died a martyr. His right hand is open on his chest, and with his left hand he is holding a parchment with the inscription: “S. Matheus dixit: Inde venturus est judicare vivos et mortuos”. The angel, the symbol identifying him as an evangelist, is shown bottom left. While the reproductions of the other apostles were made using organic manual modelling techniques, the 3D reconstruction of the statue of St. Matthew has been developed with three-dimensional scanning, which allows greater fidelity from a strictly metric point of view but requires effort for the selection and definition of details and for the elimination of redundant elements. In the 3D model realized the extremely effective rendering of the face and the geometric precision of the letters in the parchment can be detected. On the contrary, the dress and the angel requested the elimination of excessive and spurious details. The third apostle is James the Younger (3D model of Matteo Casarini, Alice Pianetta, Debora Quaini, Andrea Rozza), son of Alpheus, who according to the “Golden Legend” [medieval collection of hagiographic biographies, composed in Latin by Jacopo da Varagine (1230-1298), indispensable reference for interpreting the symbolism and iconography included in paintings of religious content] celebrated the first mass in Jerusalem, of which he was first bishop. James holds his robe in his right hand, while he is holding a parchment in his left hand that reads: “S. Iacobus Alphei dixit: Credo in Spiritum Sanctum”. The fourth apostle of the rear side is Simon Canaanite (3D model of Debora Quaini, Andrea Rozza), who is Jesus’s apostle about whom we have least information. His symbol is a saw because, according to tradition, he was martyred with that object. His parchment reads: “S. Simon dixit: Sanctam Ecclesiam catholicam, Sanctorum communionem”. The fifth apostle is Thaddeus (3D model of Zhang Qin). Words about him are only reported in the Gospel according to John 14, for the Last Supper. One tradition says that he was pierced with spears and clubs and finished with an axe for his faith, others that he was crucified. On his parchment: “S. Thadeus dixit: Remissionem peccatorum”. The last apostle represented is Matthias (3D model of Manuel Longhi), chosen by other apostles to replace Judas Iscariot following his betrayal. According to some traditions, Matthias was stoned to death. His parchment, which concludes the Creed, states: “S. Mathias dixit: Carnis resurrectionem, Vita(m) (a)eternam. Amen.”

Here follows a picture of the 3D prints.