It is not easy to determine exactly the origin of mosaics, and even the origin of the term “mosaic” is uncertain: some say it is derived from the Greek word “mosaikon” which means “patient work worthy of the Muses”; in Latin it was called “opus musivum”, that is “work of the Muses”. The reference to the Muses is due to the customs and practices of the ancient Romans, who used to build caves and crannies dedicated to the Nymphs (ninpheum) or to the Muses (musaeum) in the gardens of their mansions. It may also derive from the Arabic word “muzauwaq”, which means “decoration”, as the walls of such caves were decorated with rocks and shells. What is certain is that, with the term mosaic we refer to a work of decoration – but not only that, as we will see later on – being performed since ancient times. Over the centuries these works have become stunning art works. Some of these small parts (tiles/tesserae) are made of rocks such as marble, while others are made of stones, glass paste, ceramics, and so on. All these small parts, in different colors and shapes, are assembled and applied in different ways onto the supporting surfaces, both small and large such as floors, ceilings and domes, thereby creating fascinating decorative effects.
It is important to know that at the beginning of their history mosaics were mainly used for practical intents and not only for decorative purposes: glazed clay or pebbles were used as strong finishing materials to cover and protect walls and packed dirt floors. The first decorations consisting of base glazed baked-clay cones used by the Sumerians as finishing materials for raw brick walls date back to 3000 B.C. From the 4th century B.C. onwards and until the 3rd century B.C. mosaics were produced with marble and onyx cubes, as well as cubes of multiple rocks; after that the art of mosaic-making developed and tesserae, expertly cut, started to be used. The earliest form of tesserae mosaic in Rome dates back to the end of the 3rd century B.C. and such was used to waterproof packed dirt floors. Later on, following the expansion into Greece and Egypt, a growing interest in aesthetics and refinement developed and this led to stunning compositions and amazing effects. Originally the craftsmen came from Greece and they brought with them both the techniques and the motifs of the Hellenistic mosaic repertoire, however the Roman and Byzantine mosaics ultimately spread to the whole Empire choosing figurative geometrical motifs, arabesques and stylized plants, over the other motifs. Among the finest examples of this period we have the Basilica of San Vitale in Ravenna, Italy, and the church of Hagia Sophia in Istanbul, Turkey.
Mosaics can be made in different ways. Today mosaic works are mainly made with enamel tesserae, obtained through the melting of glass colored by metal elements (in glass-making the oxidation state of iron, manganese, and copper are important, as these elements will color the glass differently depending on their state of oxidation). The melted glass can be shaped (usually square-shaped) when hot using various techniques such as blowing, moulding, pressing or casting. Moreover, gold enamel tesserae are also used: such tesserae are obtained through the application on glass of a thin gold leaf which, after melting, gives color to the tessera. Basically any frangible material can be used, especially in modern mosaic-making: plates, mirrors, shells, bottle caps. For his works of the series “Raccolti in preghiera” Piedmontese artist Aldo Mondino even used seeds and legumes (maize, wheat, peas, beans, coffee beans) and in other works he used chocolate and sugar cubes.