The present miniature derives from a rectangular pastel portrait by Jean-Étienne Liotard (Swiss, 1702-1789), which is thought to be the one listed in Liotard's records of works supplied to the royal family as 'Le 31 septembre 1751: 1 portrait du Roy'. The picture is now in the Collection of the Fondazione Ordine Mauriziano, Stupinigi, Turin. The records also show that in May and July 1751, Liotard executed two portrait miniatures of the king to decorate boxes. For further information, see M. Roethlisberger et al., Liotard, Doornspijk, 2008, vol. I, pp. 389-391, illustrated II, pl. 287.