Fabbrica di San Pietro completes restoration of Cappella Clementina dome

The Fabbrica di San Pietro has completed a conservation restoration of the dome in the Clementine Chapel at St. Peter's Basilica. The project, which began in May 2025, addressed 371 square meters of mosaics created between 1601 and 1604 based on designs by Cristofano Roncalli, also known as Il Pomarancio.

The restoration was prompted by periodic monitoring that showed the mosaic decorations needed conservation. Workers cleaned the surfaces, removed dust and incompatible materials, and treated efflorescence. The project also included the restoration of contemporary stucco decorations to ensure the entire decorative scheme appears unified.

Before the physical work began, technicians conducted a diagnostic campaign involving laboratory analysis of materials, digital mapping of degradation, and endoscopic investigations. These efforts resulted in a digital archive that can be updated to assist with future maintenance and inspections. The scaffolding used during the process was installed in January 2025, allowing teams to study the condition of the surfaces and identify issues caused by natural material decay and previous repairs.