Isabel Marion Galsworthy, née Watson, was the daughter of Edward Watson, a retired merchant, and Margaret, née Barugh. In 1859 she married the surveyor and land agent Frederick Thomas Galsworthy. They had two daughters Ethel M. (b. ca 1863) and Evelyn J. (b. ca 1872), and four sons Frederic J. (b. ca 1866), Arthur John, Trevor and Vincent Somers (b. 13 October 1868).
The Galsworthys were a fashionable family who lived at 8 Queen's Gate, off Kensington Road, from 1869 until Frederick Galsworthy's death in 1917. They also had a house in the country, Dinorban Court at Winchfield, Hants. JW was on friendly terms with them. He knew their nephew, the author John Galsworthy, and their niece, Lilian, who married the artist George Sauter. JW became close friends with George and Lilian Sauter. George was Honorary Secretary of the International Society of Sculptors, Painters and Gravers when JW was President.
Isabel Galsworthy's name was included in a list by JW that may have been a guest list to his 1874 Pall Mall exhibition or a subscription list for his Venice etchings as envisaged in 1876 (#12714). There is a menu dated 21 November 1875 that records a sumptuous meal JW held to which the Galsworthys were invited (#06856). Alan Cole recorded in his diary that he dined at JW's on 24 March 1876 with Frances Leyland, Isabel Galsworthy and others (#03432). According to one anonymous source, on one occasion in 1877, after having lunch at her house at Queen's Gate, JW casually sketched Isabel's portrait on brown paper, Portrait of Mrs Isabel Marion Galsworthy (M.540). However, its seems that sittings were more formal with Isabel dressed in a smart jacket and hat. JW also drew their son Vincent, Portrait of Vincent Somers Galsworthy (M.541).
Post Office Directory, London, 1875; UK census 1881 from http://www.familysearch.org (accessed 2004); MacDonald, Margaret F., James McNeill Whistler. Drawings, Pastels and Watercolours. A Catalogue Raisonné, New Haven and London, 1995.