William Orpen Major Sir William Newenham Montague Orpen , KBE , RA , RHA ( 27 November 1878 – 29 September 1931 ) was an Irish portrait painter , who worked mainly in London . He was also a war artist . Life and work . Born in Stillorgan , County Dublin , William Orpen was the youngest son of Arthur Herbert Orpen ( 1830 - 1926 ) , a solicitor , and his wife , Anne St . George ( 1834 - 1912 ) , eldest daughter of the Right Rev . Charles Caulfield ( 1804 - 1862 ) , Bishop of Nassau . He was a second cousin of Goddard Henry Orpen . William Orpen was a fine draughtsman and a popular painter of the well - to - do in the period leading up to World War I . He was involved in the " Celtic revival " in Ireland and took part in the attempt there to find a visual counterpart to the birth of new national literary language ( McConkey 2005 ) . Although his studio was in London , he spent time in Ireland painting , he was a friend of Hugh Lane and influenced the Irish realist painters , like Sean Keating , who were beginning their careers at that time . Orpen ' s wife was Grace Knewstub , whom he married in 1901 and with whom he had three daughters . The marriage was not happy , and the painter eventually ran off with one of his sitters , Madame Saint - George , a wealthy young married woman whom he painted around 1912 . Like Sir John Lavery , Orpen was an official war painter of the First World War . In 1917 he travelled to the Western Front and produced drawings and paintings of privates , dead soldiers and German prisoners of war along with official portraits of generals and politicians . His large paintings of the Versailles Peace Conference captured the political wranglings and the vainglory of the gathered politicians and statesmen , whom Orpen came to loathe but relied upon for post - war commissions . Most of these works , 138 in all , he gave to the British government on the understanding that they should be framed in simple white frames and kept together as a single body of work . They are now in the collection of the Imperial War Museum in London . For his war work , he was made a Knight Commander of the Order of the British Empire ( KBE ) in the 1918 King ' s birthday honours list . He was elected a Royal Academician ( member of the Royal Academy of Arts ) in 1919 . He was deeply affected by the suffering he witnessed in the war and his " To the Unknown British Soldier Killed in France " first exhibited in 1923 showed a flag draped coffin flanked by a pair of ghostly and wretched soldiers clothed only in tattered blankets . Although widely admired by the public , this picture was attacked by the press and Orpen painted out the soldiers before the painting , which had originally been dedicated to Field Marshal Haig , was accepted by the Imperial War Museum in 1927 . According to Bruce Arnold , writing in " Irish Art a Concise History " : As noted by his biographer , H . L . Wellington , in referring to the portrait of Lily Carstairs which formed part of the Royal Academy Exhibition of 1915 , Bruce Arnold noted Orpen ' s interest in self - portraiture : his self - portraits are often searching and dramatic . In his " The Dead Ptarmigan - a self - portrait " in the National Gallery of Ireland , he scowls from the frame while holding a dead ptarmigan at head height . In a review of an Orpen exhibition at the Imperial War Museum in London in 2005 , Kenneth McConkey attributes this shallowness of Orpen ' s portraits to emotional exhaustion , resulting from his experience as a painter of war . He writes of Orpen ' s post - war activity : Orpen died aged 53 in London , and was buried at Putney Vale Cemetery . A stone tablet in the Island of Ireland Peace Park Memorial , Messines , Belgium , commemorates him . On 9 May 2010 , a painting of Orpen ' s mistress Yvonne Aubicque featured on BBC1 ' s " Antiques Roadshow " . The owner believed it to be a copy of an original in the Imperial War Museum . However , it turned out to be a " copy " painted by Orpen himself and estimated to be worth £250 , 000 .