The spread of gunpowder in the war technique brings radical changes in the fortification architecture, changing the form of the fortresses. The high vertical walls of the old fortifications are noticeably lowered, and their external side forms an intense incline towards their base. At the same time, the entire perimeter of the fortified enclosure is strengthened towards the fortress's interior with extensive infills.

The towers in the first years are built circular with relatively limited dimensions. Gradually, they cease to be towers and change into powerful polygonal platforms pushed out from the main line of defense. These so-called bastions become the dominant element of the new defense systems. The bastions are a solid construction in the form of a large square, so advanced outside the main line of defense to control as much of the area in front of the fortress as possible and provide lateral protection to the adjacent straight sections of the wall.