Canterbury cathedral, its archbishops, monks and the relics of its saints hold a prominent place in the events of the turbulent reign of King John. The disputed election to the archbishopric, resulting in the choice of Stephen Langton at the behest of Pope Innocent III, the king's refusal to acknowledge this, and the ensuing sentences of interdict and excommunication are all well known. This essay will consider specific aspects of the relationship between king, cathedral and archbishop, focusing on John's religious outlook, and on the contrast between royal actions and their portrayal in the major narrative histories of the day. It will argue that Canterbury cathedral ranked alongside Bury St Edmunds and Westminster as an important centre of royal pilgrimage in the early years of John's reign, a role that has been unrecognised hitherto. The king's pilgrimages demonstrate that the cult of St Thomas Becket was as important to John as those of canonised kings such as St Edmund the Martyr and St Edward the Confessor. In addition, John's activity stands in sharp contrast to the notion that Becket's status as a ‘political’ or ‘anti-royal’ saint in some way precluded royal efforts to appeal for the saint's intercession. After brief consideration of the influence of Hubert Walter (archbishop of Canterbury 1193–1205) on John, the essay will examine the relationship between the king and the Canterbury monks in the years 1205 to 1213, a period usually considered in terms of the struggle between king and pope over the election of Stephen Langton as archbishop.