Liber de natura rerum

De natura rerum (or Liber de natura rerum) is a thirteenth-century work of natural history, written by Flemish Roman Catholic friar and medieval writer. Thomas of Cantimpré. De natura rerum may be Thomas' most significant work, as it's both the one he dedicated more time to (almost twenty years of work, between 1225 and 1244) and the one that had the largest posthumous fortune, as witnessed by the large number of codices that contain this work, but also by the many authors that took inspiration from it.