An haeresis sit crimen. Leibniz contro Thomasius?

Since the end of the Enlightenment, Christian Thomasius (1655-1728) was seen as a hero of religious freedom and a champion of toleration. A similar portrait was caused by Thomasius’ important writings against sorcery, torture and heresy. Among them, the dissertation An haeresis sit crimen (1697) is noteworthy, also because it was criticized by Leibniz, who seems to think that heresy must be prosecuted. Does that mean that, contrarily to Thomasius, Leibniz held a conservative or even a reactionary position and supported intolerance? In the following, I will dwell upon this question, trying to show that Leibniz’ critics of Thomasius shall not be read as a refusal of religious toleration, but, on the contrary, as a different way – in a certain sense more effective – to support it.