The Weighing House was built in 1660s as a place to keep the public scales, while the central square served as the market place. This is the only building of its type that has survived in Estonia. The main attraction of the small two story limestone building is in the strict symmetry in the architecture and the scaled gable, decorating the façade. The Weighing House was enlarged with a single story building in the 18th Century, probably for stables.
The building has had numerous functions throughout the centuries. At the turn of the 18th century, it accommodated the Town Guard, at the turn of the 19th, the Town Post Station. The initial façade was restored in 1980 - 1982, by the architect, L. Hansar, and the historian, A. M. Hallik.
Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.