The Ponderaria Mensa , or public office for the control of weights and measures, was located in the forum of the city of Tibur. The building, probably of the Augustan age, was found by chance in 1883. The Ponderaria Mensa is one of the rare cases in which the specific function of public weighing has been identified thanks to the presence of two tables, made of marble and equipped with concave cavities of different size to accommodate official reference weights. An adjacent room, discovered in 1920, was probably dedicated to the cult of the emperor (Augusteum). An inscription gives us information on the creator of the exhibition, the freedman Marco Vareno Difilo, magister of the corporation of Herculaneum.