Settling in Leiden, following services under notable patrons such as Maximilian II, Holy Roman Emperor, and the Fugger banking family, Charles de l'Ecluse (better known by his Latin name, Carolus Clusius) became director of the city's new botanical garden in 1593. His knowledge of botany, acquired through his travels in Europe, allowed Clusius to translate older works on natural history and to publish his own writings on the flora of Spain and Portugal (1576) and Austria and Hungary (1583). In 1601, he combined these two works with further observations in his influential Rariorum plantarum historia (RCIN 1057452).
Aside from botany, in 1605, Clusius also published this book on rare and exotic plants and animals. Covering ten books, it is an illustrated compendium of species not well known in Europe. The work contains many references to the writings of fellow naturalists as well as several of Clusius's own observations and discoveries.