The Enigmatic Stone Slab of the Abbey of San Pietro ad Oratorium – Capestrano​. By Etruscan Corner

The church of San Pietro ad Oratorium stands in the valley of the Tirino, on the right bank of the river which, at the time, flowed 200 meters from the place of worship.

Surrounded by thick vegetation, it lies in the open countryside, in the valley dominated by the castle of Capestrano, in the province of L'Aquila, and is about 6 km from the town center.

The town was made famous by the discovery in 1934, in an agricultural field, of the Warrior of Capestrano*

The quiet of the solitary valley surrounds the landscape of the crumbling church hidden among the poplars on the bank of the impetuous river. Around the ruins, often flooded by the rising waters, a tenacious vegetation clings, a jealous dissolver of those stones composed by the patient hand of the marble worker. The monastery has disappeared; the dismantled side aisles of the church flank the central nave like a bulwark, the sole dominator of a centuries-old struggle.

These are the words with which Gavini, at the end of the 1920s, introduces S. Pietro ad Oratorium in his History of Architecture in Abruzzo.

To the left of the church portal, an ancient inscription is inserted, known as the Magic Square or SATOR.

The SATOR square could be understood as an amphibological anagram, deliberately containing multiple keys to interpretation that revealed themselves differently depending on the level of knowledge and depth of the reader.

The inscribed stone block, placed in a mirrored and inverted position, bears five words:

ROTAS OPERA TENET AREPO SATOR

Less well-known but equally interesting is the stone slab present on one of the external façades of the church with 4 panels and floral decorations.

We submitted the image of the slab to Prof. Adriano Gaspani, and below is an excerpt from his analysis on the meaning of the floral decorations present. Prof. Gaspani, a renowned archaeoastronomer, has already prepared a report for us regarding the Grotta delle Stelle.

San Pietro ad Oratorium

The church of San Pietro ad Oratorium (8th – 12th century) is part of an ancient Benedictine monastery built in 722 by order of the Lombard king Desiderius, as stated by the inscription placed on the lintel of the entrance:

A REGE DESIDERIO FUNDATA MILLENO CENTENO RENOVATA

Others, however, consider that the complex was founded by Pope Stephen II in 756. The monastic settlement was established to control a vast landed estate, consisting of the Tritana Valley, and is located at the point where the valley narrows not far from the ancient route of the via Claudia Nova and the Tirino river.

The Romanesque Reconstruction

Over time, the convent was completely destroyed, while the church underwent a radical reconstruction around 1100. The new foundation was consecrated in 1117 by Pope Paschal II.

The architecture of the church consists of a longitudinal building with three naves ending in as many semicircular apses. The naves are rhythmically divided by pillars supporting round arches. The presbytery is raised above the hall and upon it stands a 13th-century ciborium.

The layout is Romanesque and the roofs are wooden trusses. The façade, which has a single entrance portal, shows the original stone facing.

A Mysterious Stone Slab

On the façade of the church of San Pietro ad Oratorium, a stone slab is walled, probably dating back to the foundation of the older church, that of probable Lombard origin, which bears four sectors, each of which is delimited by a small arch-shaped high relief enclosing some motifs considered floral, but which in reality could also have another explanation.

The Philosophical Study of Nature in the Middle Ages

With philosophy of nature or natural philosophy, it is customary to indicate, in the Middle Ages, a sector of theoretical philosophy that examines the physical reality of the entities constituting the material world. […]

The attention towards Creation conceived as a set of physical entities interacting with each other is an aspect of philosophical reflection already present in the early Middle Ages, which concentrates particularly in readings of the biblical Genesis and Plato's Timaeus. […]

With the spread of translations of these texts, and, at the beginning of the 13th century, with the foundation of the first Universities, attention to these themes reached such a level that it was considered, in ecclesiastical circles of that time, a threat to Christian culture, since, alongside explanations of the physical world, some ideas were proposed that sharply contrasted with the dogmatic truths of faith contained in sacred texts. […]

Particularly significant were the studies dedicated to the problem of the movement of celestial bodies, which discussed the Ptolemaic and Aristotelian thesis of the centrality and fixity of the Earth in the particular planetary context and the broader context of the Universe as a whole. […]

Astronomy and Cosmogony in Medieval Europe

In the early Middle Ages, due to the fall of the Roman Empire and the spread of Christianity in the Western world, a new direction in philosophical research was determined. Christianity brought men back to spiritual interiority, precisely by virtue of its cornerstones; to this was added the precariousness of existence due to the historical situation.

Therefore, initially medieval thought, cultivated by men of the Church, was mainly concerned with religious problems, while everything that was not spiritual but was part of man's external experience took a back seat.

However, with the evolution of cities, culture, the economic rebirth, and following the gradual rediscovery of classical Greek and Latin works, the latter thanks to contacts with the Arab world, the need to study nature and its manifestations began to be felt again, something that in the pre-Christian world was established practice. […]

Great cultural importance was held by the School of Chartres, among whose most prominent exponents we should remember Thierry of Chartres (died around 1154) who developed his own interpretation of creation, according to a completely original mechanistic model, albeit decidedly fanciful and picturesque.

According to Thierry of Chartres, God created the four fundamental elements: air and fire which constitute Heaven, and water and earth which constitute the Earth, arranging them in concentric spheres. The sphere of fire, rotating, illuminates the air and causes the distinction between day and night, subsequently it vaporizes the water separating it from the earth on which its heat creates life and gives rise to the appearance of man in the image and likeness of God. […]

With the fall of the Roman Empire, the medieval period began in Europe, a period in which the development of the sciences came to an abrupt halt. However, the arrival of the Arabs in southern Europe, particularly in Spain and Sicily, and the presence of the Irish monastic clergy on the European continent, determined the maintenance of a flourishing astronomical culture that would influence future generations of intellectuals and the technical and symbolic conceptions of the guilds of medieval architects who in subsequent centuries built churches and cathedrals.

Astronomy and Astrology in the Middle Ages

In the Middle Ages, Astrology was considered the «Queen of sciences». At that time, it was one with Astronomy.

Based on Greek cosmology, Christian theologians identified nine fundamental heavens, the first seven corresponding to the orbits of the planets visible to the naked eye: composed of a spiritual, ethereal substance devoid of any flaw, they contained the associated planet set like a gemstone, dragging it with them in their motion; of these heavens, the highest was that of Saturn.

To these was added a heaven of fixed stars (or firmamentum) containing the Zodiac, and a Primum Mobile which gave motion to all the others.

Later, sometimes, two other crystalline heavens were added and finally the seat of God, called the Empyrean, which brought the final count to 12, an important number for Christian mysticism. […]

The organic and unitary vision of medieval cosmology was masterfully synthesized by Dante Alighieri in The Convivio (1307), which associated with each of the nine heavens a planet of Astrology, and also one of the nine angelic hierarchies of the Christian tradition dating back to Dionysius the Areopagite. […]

The Symbolic and Esoteric Medieval Representation of the Cosmos

In incorporating all these symbolic meanings, the architectural form became a symbolic image of the Cosmos and as such had to be astronomically coherent, hence the need arose to orient the place of worship in accordance with astronomically significant directions important from the point of view of Christian liturgical meaning, which moreover was very tied to beliefs and ancient pagan esoteric traditions of eastern origin, particularly from the Indo-Iranian world.

The sacred building was an image of the macrocosm created by God, but also represented the microcosm constituted by Man. The center of the architectural form, analogous to the unitary center of the Universe, was also the innermost center of every being; the body of the temple was symbolically identified both with the body of the Cosmos and with the body of Man, particularly with the body of Christ who represented the link between the two and, consequently, according to Christianity, the body of man was a temple, which guarded the Soul.

By virtue of this homology between the sacred building, Man, and the Cosmos, this process could symbolically serve as a representation of the spiritual journey.

Going to the sacred center of the architectural space was symbolically equivalent to reaching the center of the Universe, but also the center of ourselves: the point of spiritual regeneration. Ritually ascending the place of worship walking along the nave was considered as returning to the supreme Center that encompassed all states of existence and states of being.

In cultures of Celtic origin, the ritual motion towards the center took place along a circular trajectory of circumambulation traveled clockwise, in agreement with the rotation direction of the apparent motion of the Sun and all the stars that populate the Celestial Sphere, as still happens today during visits and pilgrimages to the ancient monasteries located in Ireland.

The construction of a place of worship was a ritual that symbolically recomposed the discrete parts of Unity, scattered and fragmented in different manifestations, reunifying them and thus re-establishing the harmony of Man with the Universe. […]

The Representation of the Stars in Medieval Europe

During the Middle Ages, the representation of the starry sky was not at all realistic. The known constellations were drawn as figures without the stars being represented in their correct position, except for some notable exceptions, such as the constellation Cygnus due to its Latin cross shape which symbolized the Cross of Christ.

A typical and very common representation was to depict the stars using floral motifs, so for a long time, these representations were considered purely artistic, when instead they were actual star representations.

The representation of the planets during the Middle Ages was achieved using larger floral symbols compared to those representing the stars, or sometimes as six-pointed stars, except for Venus (Hesperus and Lucifer) which usually, due to its remarkable brightness, was represented as an eight-pointed star.

There are magnificent examples of this in the seals of the Knights of the Order of the Temple. […]

The Encoding of Dates

One of the medieval customs, especially before the year 1000, is the encoding of particularly important dates using a cryptic code based on the symbolic representation of stars and planets. This was especially done on stone materials which were then walled up on the walls of power buildings such as churches and castles. The date to be represented was encoded using the combination of the positions of some planets visible to the naked eye (Mercury, Venus, Mars, Jupiter, and Saturn) sometimes in combination with the lunar crescent.

The Stone Slab of the Abbey Church of San Pietro In Oratorium indicates a date using Reciprocal Planetary Configurations.

The stone slab object of this study seems to encode, according to the classic medieval scheme, an important date for the Abbey or for the church. The purpose at this point is to identify this date by examining the configurations reported on the slab and intersecting them with the results of the sky simulation for the chronological period that seems most relevant.

Here we are helped by the second panel, which contains the clear symbolic, yet quite evident, representation of the seven main stars of Ursa Major.

Ursa Major appears frequently represented on Lombard stone vestiges, with the stars depicted with floral motifs, especially in the last period of Lombard presence in Italy. An example for all is the slab of Maviorano (major slab of Gussago) placed on the sarcophagus of a Lombard arimannus, which I report below.

Based on the presence of Ursa Major on the slab of San Pietro ad Oratorium, it is possible to date its construction to the 8th century, which was then reused and inserted into the façade of the Abbey church. The representation of Ursa Major is inverted, as often happened in the early Middle Ages, as if the constellations were seen from outside the Celestial Sphere.

The first, third, and fourth panels, on the other hand, show a combination of small floral motifs, representing stars, among which are represented larger elements, eight-pointed, which according to medieval iconography would correspond to the planets visible to the naked eye. The first and third sectors contain one each, while the fourth sector contains two.

The most probable interpretation is that the slab reproduces a multiple planetary conjunction that occurred on a specific important date for the Abbey and was very visible in the sky of that period. […]

Having established that the slab could chronologically refer to the final century of the Lombard period in Italy, the ephemerides of all the planets visible to the naked eye were calculated at 1-day intervals for about a century and a half, searching for the planetary configuration that might have inspired the production of the slab with the ultimate goal of encoding an important date.

In order to evaluate the various planetary configurations, a merit function S(t) was constructed, which varies as a function of time t, assuming a maximum at time to, that is, when the best agreement occurs between the overall celestial configuration (constellations + planets) and the representation legible on the slab, according to the criteria adopted in the mathematical-astronomical model developed and used during this analysis. […]

Results of the Present Archaeoastronomical Analysis

The computerized learning system allowed identifying the planet Jupiter represented in the first sector of the slab, Ursa Major in the second, Saturn in the third sector, and the close conjunction between Venus and Mars in the fourth.

The optimal date to which the slab seems to refer was September 8, 768 A.D. at 4:10 in the morning. On that night, the planets Jupiter and Saturn were close in the constellation of Cancer, while Venus and Mars were in conjunction in the constellation of Leo near the star Regulus (α Leonis), which also appears to be represented on the slab.

Celestial situation on September 8, 768 A.D. at 4:10 in the morning, therefore before sunrise. This configuration seems to be the optimal one according to the computerized learning and cross-correlation system (CORRNET) which allowed identifying the planet Jupiter represented in the first sector of the slab, Ursa Major in the second sector, Saturn in the third sector, and the close conjunction between Venus and Mars in the fourth. On that night, the planets Jupiter and Saturn were close in the constellation of Cancer, while Venus and Mars were in conjunction in the constellation of Leo near the star Regulus, which also appears to be represented on the slab.

Meaning of the Solution Obtained

Let us now analyze the meanings of the result obtained. Firstly, the slab seems to correspond to the first foundation of the Abbey, of which it encodes the date in a cryptic manner using planetary configurations. The first foundation of the Abbey of San Pietro In Oratorium in Capestrano is ascribed to the Lombard king Desiderius (Daufer in Germanic language) who reigned from March 757 to June 774.

The solution obtained from the astronomical calculation converges on the dawn of September 8, 768 A.D., with an error margin of a few days more or less. It is therefore very probable that this date may refer to the founding ceremony of the Abbey, with the Lombard king present.
We recall that September 8 is the feast of the Nativity of the Virgin Mary. This feast was instituted by Pope Sergius I in the year 688 AD, so it was officially in force and had been celebrated for about 80 years.

Conclusion

In this study, we have attempted to assign a meaning and a chronological placement to the stone slab currently walled on the façade of the church of the Abbey of San Pietro ad Oratorium in Capestrano (AQ).

The main source of information is represented by the four sectors carved on the slab, among which three represent planets among the stars and one represents the stars of Ursa Major. The typology of the artifact places it in the era of Lombard presence in Central Italy. The foundation of the Abbey of San Pietro in Oratorium is traditionally ascribed to the Lombard king Desiderius, who reigned from March 757 to June 774.

During his reign, the Abbey was founded and, according to the results of this archaeoastronomical study, in the year 768 AD, precisely on September 8, he may have presided over the foundation works. To decode the slab and extract the information encoded within it, the most modern analysis techniques, based on artificial neural networks, were used, leading to the determination of the indicated date with a margin of error of 1 day more or less (with 68% reliability) or 2 days more or less (with 95% reliability) or even with 3 days more or less with 99.76% reliability.

The slab therefore dates back to the first abbey structure, preceding the Romanesque refoundation, and with great probability encodes its foundation date. The dating of 722, considered valid for the foundation of the Abbey, does not seem accurate, as King Desiderius was born in 720 AD (and died in 786 AD).

The dating of 768 AD, obtained from the present archaeoastronomical analysis, therefore seems more probable, although it might perhaps refer to the first foundation of the abbey church and not the initial monastic structure.