Questions of toleration, and especially of religious toleration, are prominent in modern society: should we allow religious symbols, such as crucifixes and headscarves, to be worn at school? Should we ban or restrict literature that is critical of religious faith? Does Jewish or Islamic dietary law justify exemption from the laws governing the slaughter of animals? In societies characterised by cultural and religious diversity, we need to know what justifies toleration, and what its proper limits are. However, these problems are not entirely new. Indeed, they were central to 17th century politics and philosophy. Re-visiting the 17th century debates about toleration might therefore help to cast light on the problems of our own age.