What is ‘heresy’? One answer would be, ‘that which orthodoxy condemns as such’; though we may also wish to consider when conscious dissent invites such a condemnation. The main ‘heresy’ in late medieval England was that usually termed Lollardy, understood to be inspired by the radical theological thought of John Wyclif (1328-1384), which among other things emphasised the overwhelmingly importance of Scripture, and of lay access to Scripture, through vernacular translation. Orthodox repression of heresy began in the late fourteenth century and developed in various ways in the fifteenth. There are small traces of these much wider battles in Chaucer’s oeuvre, but it would be very hard to say quite how he saw them. We might instead see the fluidity of attitude toward aspects of religion in Chaucer as a sign of his times. ‘Dissent’ can encompass more than that which is solidly decried as heresy, and ‘orthodoxy’ can turn out to be more than one mode of religious thought and expression.