The Roman city was endowed with a wall between the late 3rd century and early 4th century AD. The enclosure is oval-shaped, adapted to the natural outlines carved out by the river, with a perimeter of approximately 750 m. The wall, of robust construction, reuses abundant materials from Roman buildings, making it possible to quickly identify capitals, columns, friezes and engravings which formerly belonged to the city. It is reinforced with regularly spaced semicircular and rectangular perimeter towers. The wall’s construction reduced the urban area, excluding important parts of the city, such as residential houses and public spas. The wall underwent some later restorations and consolidations. The Templars used it as a fortress reinforced by a tower, located on the podium of the ancient Roman temple. The North Gate, flanked by two circular turrets, preserves three perfectly round arches, supported by raised imposts, with the negatives of the original hinges being visible. It faces Bracara Augusta (Braga).