One of the main sources of income for Poznań residents was trade. To ensure that merchants respected the law, their honesty was checked. It is for this purpose that the Municipal Weighhouse was established. Its ground floor housed weighing and measuring equipment that ensured compliance with specified standards. A sales volume tax was collected and forwarded to the city’s coffers.
After the Weighhouse was revamped by Giovanni Battista di Quadro in 1561, a splendid upstairs room was added to house a court of law. This was yet another institution which fulfilled the needs of the local community, which in this case was law and order.