William Cleverly Alexander (1840-1916), a wealthy banker and patron of Whistler, married Rachel Agnes Lucas. They had a large family, including several daughters: Agnes Mary ('May') (1862–1950), Cicely Henrietta (1864–1932), Helen Christina (1866-1897), Grace (1867–1959), Emily Margaret (1872-1962), Emily Margaret (1872–1962), Rachel Frances (1875-1964) and Jean Ingslow (1878-1972), and two sons, William Geoffrey (1865–1911) and George Cleverley, born about 1869 (d. after 1937).
W. C. Alexander commissioned portraits of his daughters May, Cicely and Grace from Whistler (Harmony in Grey and Green: Miss Cicely Alexander y129, Miss May Alexander y127 and Portrait of Miss Grace Alexander y130). His wife helped by following Whistler's demands for her daughters' dresses, chaperoned the sitters, and entertained Whistler as their house guest.
UK 1881 census; Pennell, Elizabeth Robins, and Joseph Pennell, The Life of James McNeill Whistler, 2 vols, London and Philadelphia, 1908 .