Jacob van Maerlant (circa 1235−1300) was arguably the most important Dutch poet of the 13th century. He produced a verse translation of the Bible (the Rijmbijbel) and an adaptation, Spiegel historiael, of the Speculum historiale by Vincent of Beauvais (died 1264), a history of the world to the year 1250. The manuscript shown here, Der naturen bloeme (The flower of nature), is an adaptation of De natura rerum (The nature of things) by the philosopher and theologian Thomas of Cantimpré (circa 1200−circa 1270). De natura rerum ultimately derives from classical sources, the oldest of which is the Physiologus, a Greek text written in Alexandria in the second century, in which some 50 animals, monsters, and minerals are described. For his Dutch translation, van Maerlant somewhat shortened the text by Thomas of Cantimpré; in 13 books, he consecutively discusses man, quadrupeds, birds, fish and other sea creatures, reptiles, insects, trees, medicinal herbs, sources, gems, and metals. The order is roughly alphabetical by (Latin) name. In this manuscript from the National Library of the Netherlands, Der naturen bloeme is preceded by a calendar for Utrecht and a number of short treatises, including De natuurkunde van het geheelal (The natural history of the universe) by one Brother Gheraert van Lienhout (flourished 1280−1320), an astrological work, and a small number of recipes. Van Maerlant’s work begins on folio 38 recto. The manuscript was produced around 1350 in either Utrecht or Flanders; the precise location is difficult to ascertain. It contains some 460 miniatures besides a number of drawings of the heavenly spheres (from folio 9 recto), some of which are unfinished. The most striking illuminations are those of homines monstruosi, strange races said to live in distant lands. Among them are cannibals, the cyclops, people with only one leg, and people with feet so large they could be used as a parasol. Not much is known about the provenance of manuscript. The Dutch Academy of Sciences acquired the manuscript in 1812 from the estate of G. Th. van der Capellen and his wife F.J. d'Hangest d'Yvoy. The earliest reference to it is in the catalog of an auction held in The Hague on September 6, 1779, which shows that it was in the possession of the Hague bookseller Cornelis van Buuren. In that catalog, the manuscript is described as “very old, but clean and well-kept” and “an excellent show-piece.”