The Reformation presented with heightened urgency the question of how to relate the system of beliefs regarded as fundamental by an established political community to alternative beliefs introduced by new groups and individuals. This chapter revisits different ways of addressing this problem, focusing on the relationship between truth and toleration. After discussing a variety of approaches, it investigates whether grounds for a general and principled theory of toleration can be found in religious truth itself and, following the tradition of natural law, in some universal truth discoverable by natural reason. The upshot is that, from a theoretical point of view, the culprit in intolerance is not in itself belief in some objective truth.