The Leiden artist Hieronymus van der Mij is only known today as a portrait painter, e.g. from the twelve portraits in the Lakenhal in Leiden, one in the Rijksmuseum and the series of professors done for Leiden University. He also owed his fame in his own day primarily to his portraits, but as Jan van Gool pointed out in 1750 (Note I), he also had a penchant for painting 'antique and modern cabinet pictures'. The main reason why these have been forgotten is that over the years they have slipped almost unnoticed into the oeuvre of Willem van Mieris, not seldom with false signatures to boot. This article presents a short survey of the history and genre pieces discovered up to now as a basis for further research. A list of works known from descriptions in old sale catalogues, but not yet traced, is appended after the catalogue. Hieronymus van de Mij (1687-1761) was the son of the bronze caster Philip van der Mij. In February 1710 he was enrolled in the Leiden Album Studiosorum. He was a pupil of Willem van Mieris, the leading Leiden painter of the day, becoming a member of the Guild of St. Luke in 1724 and for some time serving as supervisor at the Leiden Academy. During his life he made a collection of prints, which was sold at his house after his death (Note 2). The history of his Diogenes' Drinking Bowl (Cat. No. 1, Fig. 1) is an example of the fate that befell most of his history and genre paintings. It came up as a work by him at sales in 1774 and 1783 (Note 3), but around 150 years later, on 23 April 1932, it was sold in Antwerp as a Willem van Mieris. It came up again under this name in Brussels on 3 March 1936 and finally appeared yet again in 1983 as by Frans van Mieris the Elder. It is not too surprising that it was attributed to Willem van Mieris, for the landscape and figures are entirely in his style, but closer inspection reveals awkwardness in the drawing and much more minute detailing than is to be found in Willem van Mieris' work, while the fine, drauglatsmanlike style makes a rather harder impression than Van Mieris' softer, more painterly manner. The same characteristics appear in a scene with The Young Bacchus (Cat. No. 2, Fig.2), which was sold in Cologne in 1938 as by Willem van Mieris and which may be the same as a picture of the same subject seen by Hofstede de Groot in Moscow, which was signed and dated 1716. The Bacchus is an advance on the Diogenes in that it is more broadly conceived and the drawing is firmer and more sure. A signed grisaille overdoor in the Lakenhal, showing an Allegory on Overseas Trade (Cat. No.3) Fig.3), is van der Mij's only surviving decorative painting. It again shows a rather hard linear style, especially by comparison with the much softer and more atmospheric grisailles by Jacob de Wit. A chimneypiece painting of the same subject sold at Zoeterwoude on 25 June 1784 may have come from the same house (Note 5). Genre paintings play an important part in Van der Mij's oeuvre. The earliest dated example, a Family Group at Buckingham Palace (Cat. No.4, Fig. 4), is one of his best works. It was also thought to be a Willem van Mieris until cleaning revealed Van der Mij's signature and the date 1728 (Note 6). It again shows his great dependence on his teacher and also his closeness to his contemporary and fellow-pupil Frans van Mieris the Younger, whose name was also linked with this picture in the past (Note 7). A closely related work with a nursing mother (Cat. No.5, Fig.5), which in 1942 was in the Bentink Collection at Kasteel Weldam and bore the signature of Willem van Mieris and the date 1735, must date from the 1730's) as must a painting of a Woman Holding a Beer Glass in Johannesburg (Cat. No. 6, Fig.15), which is wrongly attributed to Frans van Mieris the Younger. Another work wrongly attributed to the latter (Cat. No. 7, Fig. 6) is revealed as a Van der Mij by the stereotyped faces of the women, the glances and the gestures. A work signed by Van der Mij in full, which came up for sale in Amsterdam in 1950 (Cat. No. 8, Fig.3), is probably meant as a Four Ages of Man. The date is given in the sale catalogue as 1708, but must actually be 1738. Although the influence of Willem van Mieris is still detectable in the old woman, the two younger ones reflect the elegant style of the French painters of the first half of the 18th century. Two scenes in a sewing workroom sold in the same sale as by Willem van Mieris (Cat. Nos. 9 and 10, Figs. 8 andg) are clearly by the same hand as a signed Fruitseller and Young Man (Cat. No. 11, Fig. 16), which was in the hands of Katz at Dieren in 1962. The Leiden tradition, initiated by Gerard Dou, of having the spectator look through a window crops up in a rather unusual form in two pendants in a private collection in Bergamo (Cat. Nos. 12 and 13, Figs. 10 and 11) and in a more conventional and thus possibly happier manner in a signed and dated panel of 1757 sold in Munich in 1899 (Cat. No. 14, Fig. 17) and a Poulterer's Shop (Cat. No. 15, Fig. 12) at Kasteel Singraven at Denekamp, which is very close to it in style (and again bears a false signature of Willem van Mieris). Finally, there are two more genre scenes in landscapes: a Young Woman Feeding Grapes to a Parrot (Cat. No. 16, Fig.13) in a private collection in Sweden, an early work comparable to a painting of 1706 by Willem van Mieris in Dresden (Fig. 14, Note 9), and a Young Couple in a Lanelscape (Cat. No. 17, Fig. 17), which belongs to a later period and is somewhat further removed from Van Mieris, although it was nonetheless attributed to him in a sale of 1906 (Note 10).