The Church of the Mithraeum in Sutri in the light

The environment of the church-mithraeum
The environment of the church-mithraeum seen in the “full lighting” scene. The main nave, where for the safe walk there is the new walkyway that hides the lighting fixtures for the ambient lighting, reaching the fossa sanguinis in the foreground. The lighting emphasizes the magnificent surviving frescoed portions and their colours, albeit with very low levels of illuminationPhoto©Carolina De Camillis and Riccardo Fibbi

Fascinating mysteries between ancient cults and Christianity

Work has recently been completed on the refurbishment of the lighting system of a fascinating and unique place, known as the Mithraeum of Sutri, now reopened to the public with guided visits. We thank the lighting designers Carolina De Camillis and Riccardo Fibbi, authors of the project, the architect Pietro Paolo Lateano, responsible for the Cultural Development of the Municipality of Sutri, and Daniele F. Maras, archaeologist officer of the Superintendence of Archaeology, Fine Arts and Landscape for the metropolitan area of Rome, the province of Viterbo, Southern Etruria and also director of the site, who talk about it on LUCE.

Several were the difficulties we faced in the drafting of the project, starting from the understanding of the places due to their complexity, to the historical stratification, and to the different uses in ancient times. Furthermore, the site is characterized by a considerable presence of moisture, with complex microclimatic conditions that have caused many problems of a chemical and biological nature for the conservation of the wall paintings. The issues required the adoption of precautions in the design choices. Concerning the plant engineering aspects, difficulties were encountered in crossing some parts, which were resolved by introducing containment and mitigation measures, such as the walkway for the safe use of the path and some metal pipes to contain part of the power distribution inside them, also reusing existing pipes underground, without opening new tracks. Great attention was also paid to find the best location for the electrical panel, the drivers, and the control unit for the management of the lighting scenes.

As for the outside, the entrance to the site is difficult to identify, and it is invisible from the Via Cassia, even during the day as it is shielded by vegetation and placed in a part of the cliff that is always in the shadow. We have studied a strategy of enhancement and highlighting through the lighting that is designed in an effective and dramatic way in order to make the monument perceptible in the evening and even for distant observers. 

Detail of the Nativity
Detail of the Nativity placed in the apse, illuminated with luminaires hidden behind the altar, equipped with elliptical optics Photo©Carolina De Camillis and Riccardo Fibbi

Lighting design objectives and solutions

Alongside the criteria usually used for plant design and lighting engineering in the field of restoration – minimal intervention, minimal visual impact, maintaining the physical integrity of the monument, and reversibility of interventions –, we set targets aimed at specific aspects of the unique context, such as the rendering of the understanding of the architectural space, differentiating its various historical periods with the help of lighting, underlining the spatial division of the nave and the side aisles and of the architectural elements, by balancing lights and shadows, and enhancing the decorative apparatus

In general, we used different lighting techniques for the individual architectural, artistic, and functional areas, also providing for the superimposition of the lighting effects. We hypothesised separate switch-ons in pre-set and modifiable scenarios based on the type of use and visit mode, and luminous flux adjustment systems to calibrate the lighting levels in compliance with the requirements for the conservation.

  • Two details of the frescoed portions

In particular, lighting with semi-grazing effect and projection were proposed in the project, avoiding positions that would result in grazing light effects that are not compatible with the irregularity of the decorated surfaces.

As already mentioned, for the lighting of the external front, the goal to be achieved was the visibility of the site, while inside we privileged the reading of the spatial arrangement, the different historical phases, the hierarchy of the nave and aisles, as well as the appreciation of the frescoed portions. 

For the interior, we identified the relevant design themes for the enhancement and for the suggestive evocation of the ancient space. The project focuses were the following: the architectural lighting of the central nave and the side benches of the mithraeum, in addition to the marking of the fossa sanguinis; the lighting of the side aisles with frescoed walls; the highlighting of the frescoed portions on the pillars; the underlining of the frescoes on the ceiling and of the fresco behind the altar; the lighting of the vestibule (the large frescoed wall, the perimeter tombs). 

Specific photometric selections have been associated with each theme (asymmetrical and elliptical optics, diffused from under deck, and shaping fixtures), using luminaires with IP66 protection. We chose to use LED sources with different white tones, selecting 2,700K for the space of the mithraeum, which is devoid of natural light, and 3,000K for the vestibule, which has direct access to daylight. 

The nightly lighting
The nightly lighting of the monumental front of the cliff, where the access to the church-mithraeum opens up. The tuff cliff also housed a necropolis consisting of numerous rock tombs, dug directly into the wall on different levels Photo©Carolina De Camillis and Riccardo Fibbi

The power supply and control of all lighting fixtures is done with remote and centralised DALI drivers, with the electrical panel and the control unit placed in a totem, which is in a barely visible location in the vestibule. The control system manages the switching-on and the scenes during the visits.

The lighting has contributed to the understanding of a splendid and valuable site, also thanks to the lighting scenes, in which the lights and shadows, even with very low levels of illumination, are able to make the observer read in sequence the original structures of the hypogeum, the nave and aisles of the medieval church with the remains of the most ancient decoration, that is the precious cycle of frescoes, up to the final triumph of the Nativity placed behind the altar. All this in the span of a few minutes of visitors’ stay on the site, due to the strict conservation needs.

The places and their history 
by Pietro Paolo Lateano

Together with the Roman amphitheatre of the 1st century A.D., the Mithraeum, more correctly the Church of the Madonna del Parto, is the very heart of the Archaeological Park of the town of Sutri, in the Province of Viterbo.

The valuable monument presented multiple criticalities due, in large part, to its location and morphology as an underground hypogeum. Consequently, the municipal administration have tried to preserve, in full agreement with the MiBACT and the competent local authorities, the fragile balance by means of targeted technical actions, accompanied by a strict visiting policy to the public. Unfortunately, in recent years, the interior lighting had revealed failures due to the age of the lighting sources, and consequently the rigorous restoration of the remarkable pictorial cycle contained within it risked being distorted by a perception clouded by bad and outdated technological concepts. Following these requests, the municipal administration decided to renew the artistic lighting of the monument, participating in the tender launched by the Ministry of the Environment for the “Giubileo della Luce” project, obtaining the relative funding of 100,000 euros.

The entrance vestibule,
The entrance vestibule, where there are graves excavated in the rock and highlighted by the lighting Photo©Carolina De Camillis and Riccardo Fibbi

The choice made by the Technical Offices and the Cultural Development Sector in charge to select the most expert designers for the drafting of the project, was very careful, as everybody was aware that a high and unconventional technical-scientific expertise was required to obtain a result suitable for the uniqueness of the monument. 

Through a careful historical investigation and a stringent programme of inspections and technical checks, the design team drew up the artistic lighting project, and in a few months, thanks to the active contribution of all the stakeholders of the contract and the Protection, the coveted goal was reached. Today, it is possible to visit the monument again and in a new form that allows, through the dedicated scenarios, the complete reading of the historical periods and the artistic origins of the frescoes, in full compliance with the vocations and protection of the site. It is the kind of synthesis that has always been hoped for – and very often not achieved – of a virtuous spiral in which political will, technical expertise, conservation, and tourist use find a happy union.

The tale of places full of history and legends 
by Daniele F. Maras

At the foot of the hill on which the Villa Savorelli is standing, the Church of the Madonna del Parto is a small religious building entirely excavated in the tuff. According to many scholars, the church was built on an older structure, whose architectural characteristics are compatible with those of a mithraeum, a place dedicated to the cult of the Eastern god Mithras in Roman Imperial era. The current arrangement of the Church dates back to between the 13th and 14th centuries. You enter a small square-shaped vestibule, decorated with frescoes depicting the Madonna with Saints, Saint Christopher, and above all the legend of the sanctuary of Saint Michael of the Gargano, which refers to the end of the Via Francigena, a destination for pilgrimages since the Lombard period. 

The central nave of the church is surrounded by pillars carved directly into the rock, which isolate the side aisles, and is closed by a rectangular apse, which frames the altar and a fresco of the Nativity. Along the naves and on the pillars, there are the remains of a rich painted decoration, culminating at the end of the central vault with a life-size representation of the Archangel Michael with unfurled wings and with his face in stucco relief. Originally, the underground structure was probably shaped like most of the mithraeums, with a central corridor surrounded by benches intended to host the mystical banquet of the initiates. At the bottom of the nave there was to be the image of the god Mithras intent on killing the cosmic bull, surrounded by astral symbols, as seems to be confirmed by the discovery in Sutri, in 1896, of the remains of a marble relief with this subject. 

Reverse view towards the vestibule
Reverse view towards the vestibule> Photo©Carolina De Camillis and Riccardo Fibbi

The so-called Mitreo di Sutri is therefore a place of ancient mystical suggestions: formerly the seat of pagan cults destined for a few initiates, it was opened to pilgrims on the Via Francigena under the aegis of the Archangel Michael, perhaps already in the Lombard times. Subsequently, at least from the end of the 13th century, the cult turned to the Virgin Mary, protector of pregnant women.

 Client: Comune di / Municipality of Sutri (VT); Responsabile Area Tecnica Settore IV / Head of Technical Area Sector IV: F. Lupi; RUP (Sole Responsible for the Procedure): A. Calcavento; Responsabile Area Sviluppo Culturale / Head of Cultural Development Area: P.P. Lateano
High Surveillance: Sabap-rm-met, F. Cerroni, D.F. Maras, soprintendente / superintendent M. Eichberg 
 Lighting design and construction supervision: RTP (Temporary Group of Professionals) Carolina De Camillis (capogruppo / group leader) con / with Riccardo Fibbi e / and Chiara Achilli
Contractor: Edilerica Appalti e / and Costruzioni S.r.l.
Lighting Fixtures: Daisalux, Elcom, iGuzzini, Ligman, Linea Light, Platek
Photos: Carolina De Camillis e / and Riccardo Fibbi

Thanks to SABAP, for the metropolitan area of Rome, the province of Viterbo and Southern Etruria, for granting the use of the images

This article was originally published on LUCE n°334, 2020