Juan Eusebio Nieremberg, an early seventeenth-century Spanish Jesuit exegist, philosopher, and scholar, was a prolific writer in several fields. Nieremberg based his book of natural history largely on the earlier work of Francisco Hernandez, physician to Philip II, who, in the 1570s was sent by the king to study medicinal plants, animals, and minerals in New Spain. Nierembergs book contains about 160 descriptions of plants, animals, and minerals. Note that many of the Nahuatl (Aztec) names for animals and plants are used in this book.