It is likely that this box originally had another cover, replaced at a later date by this micromosaic. The image represents the burnt out interior of St Pauls Outside the Walls, in Rome. The fire started during repairs to the roof in 1823. Pope Leo XII called for contributions from all over the world to restore the damage. The Church was rebuilt in 1854.

Micromosaics have their roots in the larger mosaics of ancient Rome used to decorate their walls and floors. The first micromosaics were created in the 18th century, but it was not until Arthur Gilbert himself became interested in collecting them and invented the term 'micromosaics' that they became known as such. The tesserae are minute pieces cut from thin pieces of glass known as smalti filati, and some of the finest micomosaics can consist of as many as 5,000 tesserae per square inch (ca. 3 by 3cm). By the late 18th century Rome had become central to the production of micromosaics and sold them as souvenirs to wealthy foreigners visiting the city. From small elegant snuffboxes to large monumental tabletops, micromosaics could be used to decorate objects of all shapes and sizes. They could even be made to resemble full-sized canvas paintings, and indeed Arthur Gilbert himself mistook his very first micromosaic for a painting. When he brought it home to show his wife, he had to convince her that it was not in fact a cracked painting, as she supposed, but a mosaic.

Sir Arthur Gilbert and his wife Rosalinde formed one of the world's great decorative art collections, including silver, mosaics, enamelled portrait miniatures and gold boxes. Arthur Gilbert donated his extraordinary collection to Britain in 1996.