Cronists jesuitas presented to the European reader a large collection of texts describing, among other things, American nature. Jesuitas parents used as epistemological tools in the narrations about America and its nature, on the one hand, the personal experience of travellers who witnessed what they talked about and, on the other hand, knowledge of native languages. It was this combination that enabled them as faithful witnesses. It should also be borne in mind that an important validation criterion was its membership of the Order and its services to Catholic crowns. The Illustration generated new conceptual tools for epistemological support and severely questioned the humanist devices used by the authors jesuitas.