St. Peter's Baldachin will be restored in preparation for Jubilee 2025. Last restored in the 18th century

Two hundred and fifty years after the major eighteenth-century restoration of the Baldachin of St. Peter’s Basilica and exactly four hundred years after work began on its creation, the masterpiece will be restored in preparation for the upcoming Jubilee of 2025. It was Urban VIII, in the summer of 1624, who entrusted the Superintendence of the work to the 26-year-old Gian Lorenzo Bernini, his trusted architect and sculptor, who was assisted in this undertaking by Francesco Borromini and a large group of talented sculptors, foundrymen, carpenters and specialized workers. It is therefore a “restoration of great symbolic value,” “demanding and necessary,” as was stated during the press conference presenting the interventions, which will be completed in December 2024, shortly before the opening of the Holy Door. The restoration is entirely supported by theOrder of the Knights of Columbus, and is in continuity with the project for the enhancement and new lighting of the Vatican necropolis, also supported by the Knights of Columbus.

The intervention, the Holy See points out, will be a particularly complex and articulated activity due to the importance of documentation, logistics, archival research, scientific investigations, scaffolding, the organization of the construction site in conjunction with the activities and liturgical life of the basilica, and the diversified conservative interventions. Provisional and site works, however, will not prevent the holding of papal celebrations on the high altar. The estimated time for the intervention is ten months, including the time for procurement, assembly and disassembly of the provisional works. Work is scheduled to begin in the second week of February.

“The Baldachin, the only work in which the collaboration between Bernini and Borromini is seen, is an amazing processional-inspired ’machine,’ unique in its monumentality,” explains engineer Alberto Capitanucci. “Nearly 30 meters high and over 60 tons in total weight, marble plinths about 2.5 meters high and bronze columns decorated in gold about 11 meters high that support, on the four sides, decorated cornices and draperies. The ceiling is made of wood, embellished with gilded bronze elements. The angels on the crowning measure nearly 4 meters in height, and the four tripartite volutes detached from the top of the attic support at their apex the four large bees, decoration of the base of the globe surmounted by the Cross.”

“The examination of the state of preservation of the Baldachin,” Capitanucci continues, “as far as can be ascertained, seems to exclude major degradation of the metal, on the other hand cannot fail to detect the presence of heavy dark patinas due to fatty substances and atmospheric particulate matter now incorporated into the patinas. A similar condition is found on the tombstone elements, with particulate matter adhering to the surfaces, marble inlays in the process of detachment, and gray patinas due to oxidation of applied protective agents. The wooden roofing, analyzed thanks to the recently concluded refined drone-mediated photographic survey campaign, shows extensive disconnection of the system of planks that cover the cornice, and where the elements are already detached, accumulations of particulates and semicoherent residues are evident. The ’sky’ of the Baldachin, with the radiant Holy Spirit, shows numerous disconnections and detachments of the planking, and the polychrome surfaces and gilding are plagued by widespread falls of layering and de-adhesive uplifts. Recalling how the progression of degradation over time responds to a logic if not of geometric progression, certainly more than linear, it must be concluded that today a restoration intervention is, more than a good practice, a real need for the preservation of the asset.”

The intervention is divided into the following phases:

- PROVISIONAL WORKS AND FACILITIES. Design of the working scaffolding and site facilities on the ground and in elevation (FM electrical and lighting, hydraulic and load lifting, surface shielding). The design involved the use of only “first service” materials and components and adopted a static scheme that would allow approach from the ground limited only to the columns up to a height of about 6m above the altar dais. The outer surfaces of the scaffolding around the columns, those of the middle and top entablatures, as well as the intrados of the deck below the canopy ceiling, will be completely screened with sheeting. Climbing stairs are provided on the back side of the two west columns.

- PRELIMINARY AND IN-PROGRESS DIAGNOSTICS - GRAPHIC AND PHOTOGRAPHIC DOCUMENTATION. The surveys and investigations-already scheduled to begin in the last week of November for the accessible parts-involve collaboration with the Scientific Research Laboratory of the Vatican Museums and will involve all parts and components of the work that differ in material and/or masterful execution. Preliminary to the work, when the scaffolding is assembled, a graphic and photographic documentation of the current state will be carried out. This will be followed by specific documentation of each stage of progress of the work. Information noted during construction will be reported on photographic bases. An ultraviolet fluorescence photography campaign is also planned.

-RESTORATION INTERVENTIONS.

(a) Restoration of metal surfaces (bronze and iron). The present layers of impurities and dirt will be removed with solvents and compresses, without acting on the original patinas nor on the gilding, aiming to free the bronze, part burnished and part gilded, from the superimposed layers that obscure its splendor. The operation will be completely manual. At the end of the cleaning operations, conservation and protective treatments, where necessary color balancing and eventual reintegration will be carried out.

(b) Restoration of stone surfaces. Inconsistent dust deposits will be removed by means of vacuum cleaners and soft brushes, and then partially adhering deposits will be removed by means of deionized water compresses, adhering deposits by means of ion exchange resins or manual mechanical means and ultrasonic equipment. Old grout will be removed where by composition or alteration or deterioration they are incompatible with the conservation or aesthetic function. Finally, flakes and fragments will be reattached, grouted with lime mortar and marble dust, and the surface will be protected with cloth-pulled microcrystalline wax.

(c) Wooden structure restoration. As far as the structure is concerned, after securing the detached or disconnected planks, the particulate sedimented on the surfaces and in the recesses will be removed, a preliminary biocide treatment will be carried out and then a ricohesive and re-adhesive consolidation will be carried out by means of resins and clamping. Disconnected or semi-disconnected applique elements will be disassembled and reassembled, with correction and reinforcement of the support systems. Missing portions along the mixtilinear bracket frame will be reconstructed with new cut and molded elements. The small lacunar portions will be reconstructed in modeled wood. Surface conservation treatments will consist, first, of re-adhesive consolidation by resins of the parts protected by prior glazing. The color fields will be cleaned by absorption and dry rubbing, the layered repainting on the polychromes and gilding judged to be improper will be removed, and the depth gaps restored. Subsequent color reintegration and balancing will then be followed by the application of a final layer of protective varnish.

In addition to general logistics, coordination of transportation and access, the Fabbrica di San Pietro will be responsible for preparing and protecting the Altar and predella, setting up areas for temporary storage of materials and components, and providing personnel from outside companies with suitable spaces for changing rooms and storage of consumables. In addition to Construction Management, the Factory will also provide safety coordination during both the design and execution phases.

The Baldacchino construction site will see an innovative approach in terms of the management of technical documentation, both that which will be acquired during construction (photographs, laboratory investigations, notes on the consumables used, etc.) and that which already exists. Thanks to the collaboration with Microsoft and the Italian National Fire Department, related to the full digitization of the Basilica complex, it has already been possible to extrapolate a solid geometric survey of the Baldachin that will form the BIM-H (Building Information Modeling - Heritage Heritage) for the archiving and management of the data both with a view to the conservation management of the asset and the scientific studies and insights that, in a perspective of natural involvement of the world of research, will frame and follow up the intervention.

"Generally these have been occasional interventions, carried out in a partial manner and sometimes determined by damage caused by careless maintenance work that required urgent interventions, added Dr. Pietro Zander. “More rarely have ’extraordinary maintenance interventions’ been carried out in a complete and systematic manner. Among these, the 18th-century ’restorations,’ eloquently documented by the precious papers of the Historical Archives of the Fabbrica di San Pietro, deserve special attention. In fact, the last major and radical intervention on the Baldachin of St. Peter’s dates back to the year 1758: a large team of workers and skilled laborers worked on it for about three months (up to sixty people a day). The canopy was then thoroughly cleaned, the many oxidations were removed, several components were consolidated and secured, damaged or missing parts were restored and redone, and, most importantly, the gilding was extensively restored or redone. It is quite clear that the critical orientation of the intervention will have to confront the modifications and additions that occurred in these now-historicized interventions and evaluate from time to time their retention or removal, in light of a search for overall balance of the monument itself and of the monument in relation to its architectural context.”

Mallio Falcioni will also carry out the necessary photographic documentation before, during and after the restoration work. In addition to multispectral photographic surveys, he will also take black and white and color photographs to document the “behind the scenes” of this important intervention.

The valuable scientific support of the Vatican Museums Directorate with the Cabinet of Scientific Research Applied to Cultural Heritage for the indispensable diagnostic investigations will play a key role in the restoration project.

Photo by Eric Drost

St. Peter's Baldachin will be restored in preparation for Jubilee 2025. Last restored in the 18th century

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