Michel Anguier had his initial training in France but lived in Rome for approximately 10 years, working with both Bernini and Alessandro Algardi. Shortly after returning to his native country in 1651, Anguier received one of his most important commissions, probably from the Montarsis family, who were jewellers to the Crown. This commission was for a group of seven statuettes of gods and goddesses, each of which was meant to represent a different psychological state. The set became widely celebrated and examples in bronze were created throughout the 18th century.
The present marble figure of Pluto is one of Anguier's seven deities, and he was intended to represent Melancholy. In a study devoted solely to this marble (Black and Nadeau, op. cit.), the authors argue that this Pluto, despite the fact that it bears the signature of another artist, is actually an autograph work by Anguier, an opinion that was subsequently accepted by François Souchal in the fourth volume supplement to his French Sculptors of the 17th and 18th centuries (loc. cit.). On the basis of engravings, stylistic analysis and Anguier's own lectures delivered to the Royal Academy, the authors build up a case that Anguier carved the marble in around 1669. However, perhaps the most convincing piece of evidence is that an isotopic analysis of the marble used for the Pluto suggests that it is from the same block as was used for the figure of Joseph in Anguier's documented group of the Nativity in the church of Saint-Roch, Paris. This latter group was carved between 1665 and 1667, and it is plausible that when the Joseph was blocked out, a large enough piece of marble remained for Anguier to carve the present figure.
If the present marble can be correctly associated with two Paris sale references of the 18th century (see provenance) then the explanation for the erroneous signature is easily understood. If the person who catalogued the marble in the 1778 Julienne sale was unaware of the authoriship of the Pluto, he might easily have suggested the name of Pierre (I) Legros, one of the best known sculptors of the later 17th century, and someone who was known to have executed numerous marble figures for the grounds of Versailles. If M. de Villemandi purchased the marble in the Julienne sale, he might have wanted to re-inforce this attribution and had the signature added. This was a common practice in the 18th and 19th centuries which often serves to confuse later art historians and collectors.