The portrait's subject was one of the foremost participants in the Napoleonic Wars and later the third Marquess of Londonderry. As a cavalry officer he acted as the Duke of Wellington's Adjutant-General during the Peninsular campaign, in 1809-12, distinguishing himself at Talavera and Fuentes d'Onoro. He then served as British Minister to Prussia and signed a treaty with Prussia and Russia at Dresden. As ambassador to Vienna, he assisted his half- brother, Lord Castlereagh, during the congress of 1814, and at other congresses at Troppau, Laybach and Verona; he succeeded Castlereagh as third marquess in 1822. Later, he was ambassador to St Petersburg in 1835, but withdrew the following year because of parliamentary opposition.
This is one of a number of portraits of the sitter executed by Sir Thomas Lawrence, who at the age of 21 was acclaimed by Reynolds as the latter's true successor and became one of the greatest portraitists of the day. Joseph Farington, the artist's close friend, thought it 'the best picture he had painted and recommended him to exhibit it'. It was completed just as Stewart was awarded the Order of the Bath, in 1813, whereupon it was exhibited at the Royal Academy, and engraved the following year.
As part of the National Portrait Gallery's development scheme, work has begun in Orange Street on a new site, situated next to the main building, which will house the gallery's archive and library, currently housed in Lewisham, as well as the administrative, curatorial and publications offices. This will allow more space for exhibitions and for an education centre. A new Conservation Studio is also planned for which funds are still needed. The appeal, which was started in 1989, has yet to raise about pounds 1m of the pounds 12m target. For further information, contact: National Portrait Gallery, 2 St Martin's Place, London WC2H OHE, telephone 071-306 0055.