Among the books in the sale catalogue of Pieter Saeraredam's library (Note I) was a virtually forgotten work on pagan mythology, Hcydensche afgoden, belden, tcmpcls en offerhanden, published in Haarlem in 1646 (Note 2). This rare book crops up again in the 1893 catalogue of Frederik Muller's stock, but the only known example appears to be in the Royal Library in Brussels (Note 3). Among the Dutch sources on the subject, most of which continue the tradition of such Renaissance mythologists as Giraldi, Conti and Cartari, the Haarlem work appears to be the least known and most curious (Note 8). It was published anonymously, bul is dedicated to the author's teacher's, the Haarlem Classicist painters Pieter Fransz. de Grebber (Note 15) and Willem de Poorter. In the dedication the author declares that he felt the lack of descriptions in Dutch of pagan temples, altars and images during his apprenticeship and delermined to make it good later, despite his failure to become an artist. The book was inlended for 'Painters, Poets and others'. It consists of two volumes. The first sections are devoled to pagan religion in general, to the idols mentioned in the Old Testament and to each of the antique gods individually. The second, divided up into countries, offers a kind of information that is rather unusual in the 17th century. Not much is known about the pupils of the two painters mentioned (Notes 10, 11), but among the names we do have (certainly not a complete list) that of Pieter Casteleyn is of unusual interest. He certainly did not become a painter, for in 1645, lert years after the beginning of his apprenticeship to De Poorter, he is recorded as apprenticed to his father Vincent, a well-known Haarlem printer, who in fact printed Heydensche afgoden. Pieter Casteleyn became a member of the Haarlem booksellers' guild in 1649 and from 1650 onwards he was to puhlish the famous Hollandsche Mercurius. In 1649 he printed Pieter de Grebber's 'rules of art', possibly as his masterpiece (Note 14). He may have found some consolation for his failure as an artist in the publication of notes on the gods, which would certainly have been of interest to his teachers, and there would have been time enough to gather the material between 1635 and 1646. He belonged to a relatively well-to-do Mennonite milieu, there is evidence to suggest that he and his brother Vincent probably attended the Latin School and the inventory of his estate made in 1676 included no fewer than 43 paintings, mythological scenes among them (Note 19), none of which contrardicts the hypothesis. If Pieter Casteleyn was indeed the author of the book, there would be some excuse for its weakness, as a youthful work by someone who had not yet found his metier. The book is a mishmash of arbitrary information presented in a totally uncritical and often muddle-headed manner. Casteleyn took over much from the 1581 Frenh edition of Cartari, with the great difference that he was not interested in the meaning, but only in the externals of the images he describes. In the case of Fortuna, f or example, Casteleyn gives a completely arbitrary list of attributes, possibly taken from the illustrations in Cartari (Fig. I), including that of Nemesis (Fig. 2), whose 'measure' he may have wrongly construed as the 'telescope' he so strangely refers to. The illustrations in the book, ten small and rathe primitive woodcuts, are not related to those in the French edition of Cartari. Indeed, in the case of that of Janus (Fig.3), it seems that the artist did not know Cartari's illustration (Fig. 4), since the rod shown there has been transformed, through a linguistic mistake, into a bundle of twigs. As, for the other illustrations (Figs. 5-10), some are of subjects not illustrated in Cartari, while the last one is a rendering in reverse of the illustration of the 'Abgott Jodute' in the Sächsisch Chronicon of 1596 (Note 24). In the title-page print (Fig. 11 ), on the other hand, which may be by Casteleyn himself, the statue of Mercury in the left foreground is a direct borrowing from Carlari (Fig. 12). Whether the Heydenschc afgoden was of any practical use to artists or had any influence on Dutch art seems doubtful, but it did have ils roots in the artistic milieu in Haarlem and as such it remains a highly curious phenomenon.