| The mosaics | Art for the liturgy
| Textile treasure | Rites and melodies | Evidence of power | Catalogue/Guide | Plan your visit | 
The nineteenth century marked the end of the technique of replacing the ancient mosaics with new ones. In 1881 Pietro Saccardo set up the basilica mosaic Studio.
Saccardo's activity is based on removing the mosaics from the wall and restore them. The original fragments are collected in wood or metal boxes, known as cassine, and made paper casts of the other mosaic surfaces needing restoration, painted tessera by tessera.
In the twentieth century, the combination of damage to the walls and mosaics demanded the strengthening of both. Luigi Marangoni invented the method of restoring from behind, removing the walling through to the mosaic mantle and therefore not losing the original placing of the tesserae. The wall was then rebuilt. This technique is illustrated by two models of the '30s exhibited in the first room.
Recent systems which strengthen the original mortars with adhesive material allow the mosaic layers to be fixed to the wall without removing them.
Since 1906 the activities of the Studio are daily registered on a journal that is regularly updated.