50 letters to and from Wyatt, 26 written by the Duke containing specific instructions for work at Apsley House. In 1820 Wyatt made alterations and extensions at the House which included the Waterloo Gallery wing, a project which ran considerably over budget and which caused friction between Wyatt and the Duke. There are also letters relating to Wyatts work on Stafford House (now Lancaster House) in London, where he was employed between 1825 and 1838 by the Duke of Sutherland
