Despite strong opposition amongst the Norwegian public, abstract expressionism started to develop during the 1950s with the work of younger artists such as Ludvig Eikaas (b1920), Jakob Weidemann (b1923), Knut Rumohr (b1916), Tore Heramb (b1916), Gunnvor Advocaat (1912-1997), Anna Eva Bergmann (1909-1987), Finn Christensen (b1920), Inger Sitter (b1929) and Lars Tiller (1924-1994). After 1960 Olav Strømme developed expressionism in a strongly abstract manner and Gunnar S Gundersen (1921-1983) used an original language of symbols within the framework of strict geometrical rules. The colourful, organic abstractions of Willy Storn (b1936), rooted in the Surrealism of the 1930s, represented the most original work of this era.