(b. 1852, London, d. 1944, Newbury)
English painter. He was the son of a Danish interior decorator and a woman of Scottish descent. At 14 he was apprenticed to the drawing office of Messrs Trollope, a London firm of decorators. While working there he attended evening classes at the National Art Training School, South Kensington, but his first important artistic contact came when he was sent to decorate a door at the home of the painter Edwin Long (1829-1891). With Long's encouragement, Clausen obtained a two-year scholarship to the South Kensington School of Art and then decided to further his training at the Antwerp Academy. After studying briefly under Professor Joseph Van Lerius (1823-1876), he began to sketch in the fishing villages along the Dutch coast; the product of these studies, High Mass at a Fishing Village on the Zuyder Zee (1876; Nottingham, Castle Museum), was his first Royal Academy exhibit and was well received.
Clausen was a founder-member of the New English Art Club (NEAC) and was committed to reforming the selection process of the Royal Academy. Clausen was the most widely respected of the NEAC painters, promoting the interests of the Glasgow Boys.
The works produced after Clausen's move to Widdington, Essex, in 1891 demonstrate a greater interest in movement and atmosphere. Clausen was so prominent in the Royal Academy by this stage that in 1904 he became Professor of Painting, a post he held for two years. In 1917 he was appointed an official war artist but because of his advanced years he was assigned to Woolwich Arsenal.
During the 1920s Clausen painted numerous landscapes around his country cottage on Dutton Hill, Essex. The success of his war commission led to several invitations to paint murals, notably Wycliffe's English Bible for the Houses of Parliament (1926), and upon completion of this project he was knighted. During the 1930s he continued to exhibit regularly at the Royal Academy.