George Agar-Ellis, 1st Baron Dover [1797-1833]; by descent to his granddaughter, the Hon. Lilah Agar-Ellis, later Lady Annaly [1862-1944], until c. 1922. (M. Knoedler & Co., London and New York); sold January 1922 to Andrew W. Mellon, Pittsburgh and Washington, D.C.; gift to his daughter, Ailsa Mellon Bruce [1901-1969], New York, by 1937; bequest 1970 to NGA.
- National Portraits, South Kensington Museum, London, 1867, no. 470.
- The Works of Thomas Gainsborough, R.A., Grosvenor Gallery, London, 1885, no. 40.
The fine canvas is plain woven; it has been lined. The picture has been very slightly enlarged by lining; there is a one-quarter-inch band of repaint along the left and bottom edges, and a thin border of retouching along the other edges. The ground is white, of moderate thickness. The painting is executed in very rich, fluid paint, applied first in thin washes, then increasingly opaquely, with some impasto in the highlights. The paint surface has been slightly flattened during lining. The large proportion of medium used resulted in traction crackle on drying, which has been retouched in the darks and in the face of the duchess. The recent natural resin varnish, lightly pigmented with black, has discolored yellow slightly.
- Gower, Lord Ronald Sutherland. Thomas Gainsborough. London, 1903: repro. opp. 66.
- Waterhouse, Ellis Kirkham. "Preliminary Check List of Portraits by Thomas Gainsborough." Walpole Society 33 (1953): 29.
- European Paintings: An Illustrated Summary Catalogue. National Gallery of Art, Washington, 1975: 144, repro.
- European Paintings: An Illustrated Catalogue. National Gallery of Art, Washington, 1985: 140, repro.
- Hayes, John. British Paintings of the Sixteenth through Nineteenth Centuries. The Collections of the National Gallery of Art Systematic Catalogue. Washington, D.C., 1992: 66-68, repro. 67.