Juan de Mariana
From the Jesuit Encyclopedia:
Juan Mariana, S.J. (Spanish: 1537-1624) was a prodigious Castilian scholar who wrote on a wide variety of subjects. He is most remembered for his 1599 book The King and his Formation which recalls an unfortunate page of Jesuit history. One of his topics was the morality of tyrannicide. He supported the proposition that a tyrant should be removed from office, killed if necessary, except by poisoning, once the people had made the decision to do so. This was quickly and solemnly condemned by the Superior General Aquaviva and later by a General Congregation of the whole Society of Jesus. Careless historians have neglected to point out this Jesuit condemnation of Juan's ideas. Spaniards paid little attention to Juan's thesis, but it caused a great stir in France partly because of the assassination of Henry IV. A century later John's name occasioned the now-familiar image of Mariane found on many French stamps. This was meant to be a play on John Mariana's name, and was used as the symbol of the French Revolution. The French extremists used John Mariana's thesis to justify the excesses of the French Revolution. (Ban, Ham, JLx, O'M, Som)
His treatise on money is one of my favorite books.