This was built above the Almedina Arch and its function was to keep watch and to defend the main access to the city within the walls.
Its construction dates back to the time of D. Sesnando (11th century) and was modified many times over the centuries. It used to be the seat of the municipal and judicial governors. Currently, the Núcleo da Cidade Muralhada and the Interpretation Centre work there, where it is possible to find out more about the history of the wall and the city in the Middle Ages.