The term 'micromosaic' is used to describe mosaics made of the smallest glass pieces. Some micromosaics contain more than 5000 pieces per square inch. The earliest attempts at micromosaic revealed visible joins between the pieces (known as tesserae) and a lack of perspective. Later artists such as Antonio Aguatti made huge advances in micromosaic technique, resulting in renderings that were truer to life. Glass micromosaic technique developed in the 18th century, in the Vatican Mosaic Workshop in Rome, where they still undertake restoration work today.

Micromosaics developed into a popular Roman souvenir in the 19th century. The works shown here are among the most ambitious works ever created in this technique which uses minuscule glass pieces just as a painter uses brush-strokes. Cavaliere Michelangelo Barberi (1787-1867) trained as a painter and mosaicist. He nonetheless postulated that technical perfection was not an aim in itself, but rather a ‘service to Rome’ and Italy. The ancient art form mosaic, its revival and further evolution were part of a revolutionary message: at a time when Italians were fighting for political union, Barberi’s monumental tables brought together iconic views showcasing the shared cultural identity of Italy and its ancient roots. The segments of this table lead the viewer on a 24-hour tour of Rome. 19th-century guide books recommended visiting the Colosseum at night, and St Peter’s Square at midday. The table also showcases the unrivalled skills of Barberi’s craftsmen and the range of sky colours available to his studio: every segment has a slightly different colouration.

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.