Over the European political scene during the 1820s one woman reigned supreme. Her effect was legendary in that charmed circle of smugly victorious sovereigns, warriors and diplomats which decided the fate of nations after Napoleon’s defeat at Waterloo. Surveying her achievement in ensnaring everybody from King George IV and Tsar Alexander I to Metternich, Canning and Earl Grey, a jaundiced female contemporary remarked: ‘It is curious enough that the loves and intrigues of une femme galante should have such influence over the affairs of Europe.’ Even as an elderly woman she was considered such a political liability that the British ambassador in Paris demanded her removal from France at the outbreak of the Crimean War.

How did Dorothea, Princess Lieven, manage it? She was not especially beautiful. The diarist Thomas Creevey, though he admired her piano-playing, thought she looked like a snipe, and Sir Thomas Lawrence, in painting her portrait, made no effort to conceal a shiny nose and over-large ears. Her allure derived instead