Probably the town was surrounded by a wood-and-earth ramparts with gates around 1261. These fortifications were destroyed during the dispute between bishop Tomasz and prince Henry IV in 1284, but several years later, until 1290, were rebuilt. Masonry fortifications surrounding the main part of the Nysa, that is the New Town, were created on the initiative of bishop Przecław from Pogorzela in the mid-fourteenth century. Within the town walls, the area of the bishop’s court has its own defense system.
Until 1414, the town was surrounded by the second defensive wall. The Old Town was still surrounded by only wood and earth fortifications with three gates. Perhaps this is related to the fact that until the 16th century it was an independent organism with its own town council. In addition, the Old Town had loose buildings with numerous gardens. The funds were used only for the maintenance of existing fortifications. Therefore it was completely destroyed in 1428 during the Hussite invasions.
In 1532, at the initiative of the then mayor of Nysa Melchior Bober, the tower at the Customs Gate leading to the Old Town was rebuilt into the gatehouse and as the only one in the town had a drawbridge. At the end of the 16th century, at the behest of bishop Jerin, the Wrocław fortificationer, Schneider von Lindau developed a early modern defense system. As a result, Nysa was surrounded by 10 bastions, 4 ravelins and a water moat. Later, around 1700, a system was created that would allow flooding foregrounds south of the fortifications, in the event of a siege. This system was used in 1741, when the suburbs were sunk by order of the then commander Roth. From 1862, the dismantling of the medieval town walls began.
Nysa defensive walls formed a closed circuit with a shape similar to a quadrilateral, with rounded corners. An additional security was the second, external wall. Within the inner walls, 28 towers and four gate towers were erected: Wrocław Gate in the north, Ziębice Gate in the west, Bracka Gate in the south-west and Customs Gate in the south, which led to the area of the Old Town. The Old Town itself did not have masonry fortifications, only a earth rampart with a stockade, although in its fortifications there were Nicholas and Robbers Gates. The entire fortifications were surrounded by a moat, fed by the rivers Nysa Kłodzka and Biała Głuchołaska.
Two gothic towers, Wrocław and Ziębice, which now serves as viewpoints, have survived to this day. Few preserved fragments of the old defensive walls can be seen, for example, at the Wrocław Tower, at Chodowieckiego street or next to the St. Peter and Paul church.
Webpage informacja-turystyczna.nysa.pl, Mury obronne.