Located in the square of the same name, across from Palazzo Pretorio, Prato's Town Hall was originally built in the 13th-century, and modified into the Neoclassical Style in 1791, probably to the plan by local architect Giuseppe Valentini. The old palace of medieval origin has a predominantly horizontal structure, consisting of buildings erected in different times and the result of various changes through the centuries: in the 15th century, for example, the ground floor on the short side was modified in order to install butchers' stalls, in line with the function of the square, which from its earliest days had housed the meat and grain market.
In the 17th century the Teatro dei Semplici, the first public theatre in Tuscany, was built here and torn down in the mid-19th century to make room for the Chancery offices. The great Council Room is the place where the town meetings have been held for over 700 years and it occupies the main side of the Town Hall, which consists of two buildings, a smaller one and a longer one, with porticoes and shops on the ground floor, bordering one side of the square of the same name.
From the outset the building played a central role in the city's political life and it still retains traces and signs of its illustrious past: on the corner of the facade one can see the Medici coat of arms placed here to pay homage to Grand duke Cosimo de' Medici, in 1550; the atrium on the ground floor contains the original of Fountain of the Bacchino by Ferdinando Tacca (its copy is in its original location, in the square), a sculpture that depicts a joyous and festive Bacchus celebrating Prato obtaining the status of City in 1653.