The building housing the Museum, the historic "Cimatoria Campolmi Leopoldo e C.," is a monument of industrial archaeology and the only large nineteenth-century factory built within Prato's medieval city walls. The architectural complex constitute the city's main cultural centre; the Museum occupies half of the space, about 4000 square metres, while the other half houses the "A. Lazzerini" Municipal Library.
The former Campolmi Textile Mill is perhaps the most important example of industrial archaeology within the Province of Prato. The large 8500 square metre complex located within the historic centre had been a site of textile manufacture since the Middle Ages. In correspondence with the current factory, prior to 1326, historical records attest to the existence of a fulling mill (a building for the fulling of cloth). It was acquired by the Church and transformed into a mill that was active throughout the whole of the eighteenth century. In March of 1863, the Mill of Santa Chiara was bought by three established entrepreneurs from Prato, who transformed it into a well-established company operating in the finishing of textiles.
At the end of the nineteenth century, the building was a double storey quadrilateral shape around a rectangular courtyard, featuring a large tank for water collection and a 40-metre high brick chimney at the centre. The factory only reached the current size and conformation in the middle of the twentieth century thanks to modifications and expansions, such as the construction of the beautiful vaulted arched dye-works, which now houses the entrance to the library. Textile production ceased in 1994.
The urban renewal, achieved by the City Council, was born from the desire to transform an industrial container, a symbol of the civil history of the city, into a cultural centre. The restoration work was strictly conservative and allowed for the preservation of the original character of the structure and the subsequent historical layers. From the old factory sign to the steam-powered boiler room, from the vaulted ceiling of the historic textiles room to the aged wood beams on the upper floor.