The building was built by the council and, according to the project leader, Juan de Sariñena, it was intended to be a marketplace for traders. It’s the first completely Renaissance building in the city and the most important 16 th -century civil construction in Aragón.

The outside of the building appears to have different levels, but the inside consists of a single large hall with a starry vaulted ceiling and units separated by ringed columns. The new Renaissance style is present throughout and can be particularly observed above the windows and in the frieze of the inscription that runs around the room. The most repeated motif is the city’s crest, which is carried by angels on the tops of the columns and carved into the keystones of the vaults. In the centre of each of the four sides appears the crest of Emperor Carlos V, held up by lions and draped in the Golden Fleece. Above the large hall is the upper floor, seen from the outside, which was used to store arms for the city. Access used to be via a spiral staircase inside an outer turret which has since disappeared.