Pierre-Joseph-Laurent de Gaillard de Longjumeau, Seigneur de Ventabren, de la Bourdonnière et de Valbonette (1709-1766) came from an important Provence family. Like many of his ancestors, he held responsible posts in the Civil Service in Aix. He was named Conseiller à la Cour des Comptes, Aides et Finances of Provence in 1729 and Commissaire du Corps de la Noblesse in 1754. His principal interests nevertheless remained those of an antiquary with a particular interest in the history of Provence. Among other projects, he played an active part in the compilation of the important Histoire de la Noblesse de Provence published in 1757-59, and then in 1760 produced his Antiquités de la ville d'Aix. An amateur engraver and noted collector, he was elected to the Academie de Peinture of Marseilles in 1756, and - like Mariette and the Comte de Caylus - became one of its 'Honorary Amateurs'. MacAndrew, loc. cit., identified and discussed fifteen drawings from his collection of over 204(?). A posthumous inventory of works of art which were not the object of donations was published by J. Boyer, Les Collections de Peintures à Aix en Provence aux XVIIème et XVIIIème Siècles d'après des Inventaires Inédits, Gazette des Beaux-Arts, 6th Period, LXV, 107th Year, Jan.-June 1965, pp. 105-7. Three further paintings by J. B. van Loo are included in this inventory.

Van Loo's portrait of the Aix amateur, J. P. de Ricard, likewise shows the sitter with a palette and brushes (Boyer, loc. cit., 1971, fig. 143, and MacAndrew, op. cit, p. 164, note 17)