The figures of Rousseau and Voltaire are after the model by Jean-Claude Rosset called Rosset Père (1706-86). Originally trained in the mediums of wood and ivory, he established himself in Paris in 1771, specialising in busts of Voltaire, Rousseau, de Montesquieu and d'Alembert, which he sold for between 2 and 8 louis. The bust of Voltaire, which the philosopher sat for in 1767, was supplied as a model for Sèvres and sold for 60 livres. A bust of Rousseau, signed 'Rosset Père A. St-Claude 1756', is in the National Museum in Stockholm (see Tardy, Les Ivoires: Evolution Décorative du 1er Siècle a nos jours, Paris, 1972, pp. 195 and 271-2)