The oldest part is the tower-house still discernible on the right (13th century), which had belonged to the family of Pipini, with a portico on the ground floor with pilasters of limestone then buffered but still visible.

The left hand part of the facade and building dates back to the 14th century and has eight elegant mullioned windows and a tabernacle.

The Grand Duke Peter Leopold of Lorraine in 1788 expressed the intention of creating a school of design in Prato.

By 1858, a collection of works in Prato were being assembled in a civic museum, housed in the nearby Palazzo Comunale.

From 1912, the Palazzo Pretorio has hosted the Museo Civico, which contains many works of art ranging from medieval times to the 19th century.