The purpose of this paper is to reconstruct a type of early modern political realism that is perhaps less widely researched in the English language scholarly context than the main stream Machiavellian type. The Italian ex-Jesuit, Giovanni Botero’s book Della Ragion di Stato (1589) is a fascinating experiment to combine some of the basic insights into arcana imperii (secrets of the state/power) made famous by the Florentine, and a refashioned Catholic teaching, as it was presented by the Jesuits. The paper tries to show the author’s motivations and his main line of argumentation. The paper starts out with a historiographical overview of the state of the art in the field of the history of political realism, focusing on two representatives of the so-called Cambridge School, Richard Tuck and István Hont. This is followed by a short reconstruction of some of the key terms of Botero’s treatise, based on the assumption that the history of ideas has to concentrate on the discourse used in a given context by the particular political agent or theorist. Next, certain contexts of Botero’s thought are examined, including 16th century Tacitism, Lipsius, and the Jesuit tradition with its links to the Salamanca school. Finally, one of Botero’s key concepts, the virtue of prudence is analysed, showing the deep-seated connections between Botero’s political realism and the ancient Greek, Roman, and Catholic traditions of practical philosophy. A postscript links the early modern discourse with the birth of the study of international relations.