Ellen ('Nellie') Millicent Sickert, née Cobden, was an English writer. She was the fourth daughter of the Radical politician Richard Cobden, and Catherine Anne Cobden, née Williams. Ellen married the artist Walter Richard Sickert in 1885. They were divorced in February 1900.
Documents vary in the spelling of her name, and it is not clear if it was Melicent, Mellicent, Milicent ot Millicent. Another birthdate, May 1859, has also been suggested.
In 1913 she changed her name by deed poll from Ellen Melicent Ashburner Cobden Sickert to Ellen Melicent Cobden.
Ellen Cobden wrote two novels, Winstons (1902) under the pseudonym Miles Amber, and the autobiographical Sylvia Saxon (1914). Her fortune helped her husband in his artistic career.
Commissioned by Walter Sickert, Whistler painted a couple of portraits of Ellen around 1885-6, Arrangement in Violet and Pink: Mrs Walter Sickert y337 and Green and Violet: Portrait of Mrs Walter Sickert y338. Walter Sickert bought A White Note y044 and exhibited it at the New English Art Club. He later passed it on to Ellen.
Ellen also owned The Opal Sea m1041 and a portrait of Maud Franklin that she later returned to Whistler. This may have been A Portrait: Maud y186 or Harmony in Black, No. 10 y357. Whistler remained friendly with Ellen even after his 1897 quarrel with her husband.
Times, London, 25 July 1912, p. 1; Young, Andrew McLaren, Margaret F. MacDonald, Robin Spencer, and Hamish Miles, The Paintings of James McNeill Whistler, New Haven and London, 1980 ; MacDonald, Margaret F., James McNeill Whistler. Drawings, Pastels and Watercolours. A Catalogue Raisonné, New Haven and London, 1995 .