In the 17th century Norrköping’s main defence on the Baltic side of the city was a daunting fortress completed in 1639.
It was in the shape of a five-pointed star and at the centre of its system of ravelins and bastions was a residence intended for Duke Johan of Östergötland, son of King Johan III and nephew of Karl IX. In 1719 the whole fortress was raised to the ground by Russian troops, leaving only the gate-tower, which was restored in 1930s.
