It is not certain which of Sir Henry Cole's daughters was known to Whistler.
Sir Henry ('King') Cole was a civil servant, industrial designer and museum director, and married Marian Fairman in 1833. His third brother Charles was a schoolmate of Francis Seymour Haden, who became the Cole family doctor.
They had nine children: Downer Peacock (b. 1837), Letitia Marian (b. 1838), Henrietta Lindsay (b. 1839), Mary Charlotte (b. 1841, m. George C. T. Barclay), Henry Hardy (1843-1916), Alan Summerley (1846-1934), Isabella Langdale (b. 1850, m. Frank Rede Fowke), Rose Owen (b. 1852) and Charles Buller (1854-1901).
Cole, Alan S., Fifty years of public work of Sir Henry Cole K.C.B. Accounted for in his deeds, speeches and writings, 1884; Encyclopedia Brittanica On-line at http://www.britannica.com/eb (accessed 2005).