Sight of south-west tower from inside of western bailey. In 1630-th during Kristerval bastion's construction it was included in it's body.
In the end of 15AD after Ivangorod construction Livonians begun the reconstruction of Narva fortifications. Development of artillery was taken in considerations also. New artillery emplacements were designed on the river bank opposite of Ivangorod fortress, east gates were reinforced and towers of north part of the city were converted to rondels.