Complex sentence: During the 19th and early 20th centuries, the large majority of the European settlers emigrated from Scandinavia and Germany, and the state remains a center of Scandinavian American and German American culture.
Split into simpler sentences: During the 19th and early 20th centuries, a large number of European settlers entered the state who had mainly emigrated from Scandinavia and Germany. The state remains today a center of Scandinavian American and German American culture.