The period from the 14th century to the 19th is considered a Dark Age in the nation's literature though Norwegian-born writers such as Peder Claussøn Friis and Ludvig Holberg contributed to the common literature of Denmark–Norway. With the advent of nationalism and the struggle for independence in the early 19th century, a new period of national literature emerged. In a flood of nationalistic romanticism, the "great four" emerged: Henrik Ibsen, Bjørnstjerne Bjørnson, Alexander Kielland, and Jonas Lie. The dramatist Henrik Wergeland was the most-influential author of the period while the later works of Henrik Ibsen were to earn Norway a key place in Western European literature.