Historian and politician. Styled Viscount Mahon from 1816 until 1855 when he succeeded to the earldom. Tory M.P. for Wootton Bassett, 1830–2; M.P. for Hertford, 1832 and 1835–52. Under-secretary for foreign affairs, 1834–5; secretary to the board of control for India, 1845–6. Instrumental in the founding of the National Portrait Gallery and the Historical Manuscripts Commission. FRS 1827.
(See the bibliography for full references to sources)