These small ivory busts of three renowned French figures were the speciality of Jean-Claude-François-Joseph Rosset (1706-1786) whose workshop was established at the confluence of the Bienne and Tacon rivers, at Saint-Claude, in the Jura mountains. In 1771, Rosset settled in Paris and specialised in busts of Voltaire, Montesquieu, d'Alembert and other French notables. Three of his four sons followed in his profession. See R. H. Randall, Jr., Masterpieces of Ivory From the Walters Art Gallery [Baltimore], London, 1985, nos. 433 & 434, pp. 298-299.