Thanks to the generous support of Liana Marabini, the Chapter Leader of the Monaco Chapter, the restoration of the marble Sarcophagus with the Twelve Apostles, executed and supervised by the Marble Restoration Lab of the Vatican Museums, was successfully completed between 2014 and 2015.
Conservation background conditions
The initial analytical examination of the work revealed that much of the sculptural relief was illegible due to high levels of atmospheric dust as well as severe erosion.
Upon closer inspection, the surface appeared dull and unnatural. This perception was caused by the presence of a thick layer of altered waxy substances, applied during previous restorations, in an effort to revive the area affected by water flow when the work was used as a fountain basin. Sculpted surfaces, especially those depicting faces and drapery, were severely eroded.
The restorers identified extensive cracking, considerable gaps and surface areas altered by the presence of dried lichens, which left large and circular white marks on the stone strata, negatively altering the aesthetic appearance. A large lesion originating from the top edge of the sarcophagus ran parallel to the lower edge of the carved face, fracturing the Apostles’ ankles. This phenomenon was also emphasized by a large deposit of dark limestone caused by leakage and water flow from the crack. A second lesion, larger in size, was previously closed with a bronze bracket, running lengthwise on the left side of the sarcophagus, and branching along the base.
This restoration, which began with a complete preliminary study using photographic and analytic tests, was primarily aimed at repairing the cracks in the sarcophagus. This was done with infiltrations of acrylic resins made with alcohol and premixed water mortars specific for restoration. The cleaning, and regulation following test results, was performed by applying a support system, made up of a gel product, for a brief period of time in order to stabilize the work. Various mechanical instruments were used, such as an compressed air apparatus; they facilitated the removal of surface layers of gypsum in the old fillings.
For the cleaning of the section, which featured a brown limestone crust, the “Michelangelo” Laser was used. This machine permits an extremely precise and selective intervention. The applied stucco fillings are made of finely granular marble dust and lime putty. Prior to the application of the final protection layer developed by the Marble Restoration Lab, the retouching involved the use of isopropanol Gamblin organic color pigments limited to areas where lichens left traces. The central bronze bracket was also adjusted to the perimeter of the monument, so that it would no longer be in its initial central position, where it blocked the vision of the iconographic details.