Marie Catherine Sophie De Flavigny Agoult, countess d', a French authoress, known by the pseudonyme of Daniel Stern, born in Frank-fort-on-the-Main in 1805. Her father, the viscount de Flavigny, emigrated to Frankfort during the revolution. She was educated in Paris, and in 1827 married Count Hector Philippe d'Agoult. She subsequently travelled much in Switzerland, Italy, and Germany, separated from her husband, and lived with Liszt, the pianist, by whom she had children. She was afterward reconciled with her husband (who died in 1856) and regained her social standing in Paris. She wrote a series of novels somewhat after the style of George Sand. Her principal work is Histoire de la revolution de 1848 (2 vols., 1851; new edition, illustrated, 1866). She has also published Trois Journees de la tie de Marie Stuart (1856), Florence et Turin (artistic and political essays, 1862), and Dante et Goethe (dialogues, 1866).