Complex sentence: The proposed twisting tower is inspired by a Swedish fortress named Landscrona, occupied the site in early 14th century, and another fortress Nyenskans on the site until 18th century in the form of a five-sided star to maximise views for defensive purposes.
Split into simpler sentences: The proposed twisting tower is inspired by a Swedish fortress named Landscrona, occupied the site in early 14th century. Another Swedish fortress Nyenskans, existed on the site until 18th century in the form of a five-sided star to maximise views for defensive purposes.