The foundation of botanical gardens in Pisa, Padua, and Florence (1544–1545), and then in Bologna, Leiden, Oxford, Montpellier, and Germany testify to the fact that empirical knowledge was increasingly considered a necessity even in the universities, despite the fact that even at the end of the sixteenth century chairs in botany, such as the one occupied by Andrea Cesalpino (1519–1603) in Pisa, came with lower salaries than the ones given to their “speculative colleagues” who taught natural philosophy or medicine. The aforementioned catalogues of animals and plants, like those published by Pierre Belon (1517–1564), Guillaume Rondelet (1507–1566), and Ulisse Aldrovandi (1522–1605), were thus a combination of received authority and empirical observation, based on 1) a philological and critical knowledge of the classical texts, not a passive reading of them; and 2) direct observations and conversations not only with erudite peers and colleagues, but also with the so-called “invisible technicians”—fishermen, sailors, and peasants who had first-hand knowledge of the relevant subjects and provided scientists with important pieces of information.  Not by chance, in a little-explored field like the study of minerals, the most significant contributions came from self-described “men without letters” (meaning not Latinate), such as Leonardo da Vinci (1452–1519) and the potter Bernard Palissy (1510–1589), who identified fossils as the result of organic processes rather than abstract virtues.