Ryskamp, Charles, ed. Sixteenth Report to the Fellows of the Pierpont Morgan Library, 1969-1971. New York : Pierpont Morgan Library, 1973, p. 111.
Preparatory drawing for Copley's painting, "The Siege of Gibraltar," at the Guildhall Art Gallery, London. The painting was executed in 1785 to commemorate the then recent siege. Copley completed a number of drawings, portrait studies and oil sketches relating to this painting. The composition of the drawing in the Morgan collection occurs in an oil sketch at the Thomas Coram Foundation in London, but not in the final version of the painting.