The Catholic Church in France threatened the crown with withdrawal of financial support unless it effectively suppressed the circulation of the book. The list of people writing refutations of the work was long. The prominent Catholic theologian Nicolas-Sylvestre Bergier wrote a refutation titled "Examen du matérialisme" ("Materialism examined"). Voltaire hastily seized his pen to refute the philosophy of the "Système" in the article "Dieu" in his "Dictionnaire philosophique", while Frederick the Great also drew up an answer to it. Its principles are summed up in a more popular form in d'Holbach's "Good Sense, or Natural Ideas Opposed to Supernatural".