the defensive walls belonging to the roman bridge are located in this town, by the river bank, considered the oldest town in all portugal and capital of the alto minho region until the 15th century. there are only 5 round arches on the river’s south margin belonging to the old roman bridge, which contrasts with the tudor like arches corresponding to the late medieval reconstruction. given its unquestionable cultural value it is considered national patrimony by the portuguese government.
the city’s late medieval outer walls had an irregular oval geometry, quite extensive, spanning over 1 kilometre wide. defended by a barbican, it was originally reinforced by nine towers and included the gothic style bridge also defended by two towers: the old tower to the north, and the bridge tower on the other end, incorporated in the city’s defence. the tower of the castle was built, later on in the 15th century, further south next to the citadel.