The restoration of the magnificent thirteenth-century polychrome mosaics on a gold background that cover the dome of the Baptistery of San Giovanni in Florence and which were a source of inspiration for Dante’s Divine Comedy has begun: once the construction of the imposing site has been completed, the first phases of the intervention that will last a total of 6 years, with the expected conclusion in 2028.
More than 100 years after the last restoration of 1898-1907, the more than 1,000 square meters of mosaics – made with 10 million polychrome tesserae of sizes ranging from 5 to 20 mm per side – will be the subject of an intervention aimed at recovering the structural stability and their adherence to the vault, arrest the phenomena of deterioration and bring to light the splendor of the gold background and the vivid colors of the glass tesserae.
For the first time it will be possible for the public to see the mosaics of the dome up close, made on preparatory drawings by artists such as Cimabue and Coppo di Marcovaldo, which on either side of the grandiose scene of the Final Judgment narrate the Stories of Genesis, by Giuseppe Jew, of Christ and of the Baptist. A unique and unrepeatable experience, which will only be possible to experience during the years of restoration. The visits will start from 24 February 2023, by booking on the Opera website: https://duomo.firenze.it/it/630/visite-esclusive.
The construction site and the restoration work are commissioned and financed by the Opera di Santa Maria del Fiore in agreement with the Archdiocese of Florence, under the high supervision of the Superintendence of Archaeology, Fine Arts and Landscape for the metropolitan city of Florence and the provinces of Prato and Pistoia. The construction site is a project by the Opera di Santa Maria del Fiore with Tecno System Appalti and Layher Spa while the intervention was entrusted to the Archaeological Conservation Center which, among the many restored mosaic masterpieces, boasts those of the famous Monastery of Santa Caterina on the mount sinai.
Starting in 2014, the Opera first restored the exterior of the monument and then the internal parts with mosaics, financing the work with 4 million 600 thousand. The same amount will be invested in the restoration of the mosaics in the dome, for a total of 10 million euros.
In order to be able to restore the mosaic vault of the Florence Baptistery, it was necessary to design and build a technologically innovative construction site capable of making the entire mosaic surface of the vault accessible (over 1,000 m2) and at the same time having minimal visual impact on the ground , thus leaving visible to visitors (1 million and 215 thousand in 2022 alone) the walls and purse beautifully decorated with marbles and mosaics, the restoration of which was completed in July last year. After a long period of gestation, the solution identified was to build scaffolding in the shape of a mushroom (height 31.50 m and diameter 25.50) which extends over a surface area of 618 square meters which can be walked on in the upper part, against a surface occupied on the ground of only 63 square meters. The scaffolding, built with 8,150 elements, uses the latest generation aluminum beams (Layher Flex), which passing through the quadrangular openings that overlook the attic floor of the Baptistery, allow for uniform distribution of the loads on the load-bearing structure of the monument.
The restoration of the mosaic dome of the Baptistery of Florence, which for over a century no one has been able to examine and study up close, will be able to make use of the experience gained in the previous restoration of the internal walls of the Baptistery and of the information acquired on past restorations and in particular that of the 1898 – 1907 made by the Opificio delle Pietre Dure.
On the basis of the latter’s final report, it is hypothesized that the intervention will have to deal with a situation which presents: a surface of 344 m2 of ancient mosaic, laid on original mortar, probably in the detachment phase; 567 m2 of mosaic surfaces detached and re-laid onto cement mortar from the Opificio; 128 square meters of fallen surfaces treated with decorated plaster in the intervention of 1820 – 1823 and then redone with mosaics in the last restoration.
In these days, the diagnostic investigations necessary will begin, not only to verify detachments or detachments but also to define the degradation of the tesserae, the composition and state of health of the various materials that make up the work. On the basis of all the graphic, photographic and diagnostic information acquired, it will then be possible to outline in detail the specific intervention methods for each problem, identify the most appropriate and innovative materials and then proceed with the actual restoration.
Dominated by the figure of Christ the judge, the mosaics of the dome of the Baptistery were a source of inspiration for the representation of Hell in Dante’s Divine Comedy. Around 1225, according to the date inscribed in the baptistery’s scarsella, work began, probably with recourse to mosaic artists who had come from outside and to kilns already active elsewhere. But soon the Florentine artists were able to gain full autonomy, and by the end of the century the more than one thousand square meters of the dome had been cloaked in a glittering mosaic dress.
Several generations of artists succeeded one another on the scaffolding to create a spectacular anthology of art, both pictorial and mosaic, which also includes the vault of the scarsella, whose mosaics were created while those in the dome were still being worked on. Once this colossal undertaking was completed, it was decided to extend them also to the parietal areas, where they were not originally foreseen.
THE PREVIOUS MAINTENANCE AND RESTORATION WORKS AT A GLANCE
From the archival research, which proceeded the restoration project, news emerged documenting maintenance interventions starting as early as 1300, made necessary due to water infiltrations from the roof which had damaged the mosaics. We know that the artist Agnolo Gaddi was commissioned for the first intervention and subsequently, starting from 1483, the Opera assigns an annual income of thirty florins to the painter Alessio Baldovinetti to verify the stability of the mosaics and intervene punctually where necessary. Over the following centuries further maintenance interventions will be carried out, among which, the most important will be that of 1781 – 1782 by the Florentine painter Giovanni Orlandini and Giuseppe Sorbolini which however did not prove useful because in June 1819 it had already detached a large section of mosaics and painted plaster. Thus it was decided to intervene again, painting the areas where the mosaics had fallen, instead of redoing them in mosaic, and for this the painter Luigi Ademollo was commissioned, who worked there from 1820 to 1823. Ademollo also used large plates of iron to fix the mosaics, a solution that turned out to be completely ineffective so much so that at the end of the 19th century when the Opera commissioned the Opificio delle Pietre Dure, then directed by the superintendent Edoardo Marchionni, the fall of large areas of mosaic was imminent. Thanks to the final report of the Opificio we know that the mosaic vault was restored for 1032 m2. Of these, the 128 square meters fallen and painted in plaster by Luigi Ademollo were redone in mosaic thanks to the cartoons of the painter Arturo Viligiardi, using the ancient fallen tiles and the new ones ordered in Murano. Few of the other 911 m2 were attached to the vault and the Opificio decided to detach 567 m2 and re-bond them with a mortar containing a portion of slow-setting cement.