Built towards the end of the 13th century, the ancient town hall called Arengario (from the Latin arengarius, deriving from the Germanic hari-hring, place for gatherings) stands quite contiguous to the Duomo, thus visually representing the opposing religious and civic powers marking even in Monza the Age of the city states.
Situated in the city centre, neighbouring the large ancient market square and along an axis aligned with the main road linking up the town with Milan and Brianza, it was part of a complex group of buildings now reduced by construction and restoration events to the only town hall. Next to it there was, connected by a suspended passageway, the praetorian palace (or Podestà palace), today disappeared. Place for trading and meeting point, the large arcade, propped by solid stone pillars, is situated on the ground floor of the ancient Town Hall. On the first floor a single large hall covered by wooden trusses, used for meetings and assemblies, opens into a small loggia (the “parlera”) where the decrees issued by the city state were read to the people. On the north side is the Ghibelline crenellated bell-tower with swallowtail indentations.
The entrance to the upper meeting hall, now used for exhibitions, was previously on the eastern side, where traces of two outer stairways are still visible. The actual entrance is from the north through a stairway inside the tower.