Inside the church of the monastery of St. Catherine in Sinai a 6th century wall mosaic can be found. This mosaic represents the Transfiguration. It covers the apse and the vault above and is one of the most important examples of Early Byzantine art. The deterioration of the mosaic mainly concerns the preparatory layers: the surface is affected by loss of adhesion between the preparatory layers and the masonry support. The whole surface has been darkened by deposits of dust and smoke dulling the bright colors of the tesserae. Two works of restoration in 1847 and 1959 respectively are known to have been carried out.
On November 2005 the CCA, Centro di Conservazione Archeologica of Rome started a conservation program of the mosaic surface. The intervention consists on consolidation and cleaning of the mosaic, treatment of the lacunae, protection of surfaces. Any operation is accurately documented. The presentation will report the actual state of the conservation program.