Veneration of St Katherine in Normandy can be traced back to the early eleventh century, shortly after the cult had begun to make headway in Italy. Unlike the Orthodox East, Katherine’s relics appeared first and the liturgical and hagiographical aspects of her cult followed later. Normandy can, therefore, be regarded as an early example of the second stage of development of the cult, once relics of Katherine had become available. The catalyst was the acquisition of primary relics of St Katherine by the newly founded monastery of Holy Trinity, Rouen. 1 The monastery and its relics prospered and, by the late eleventh century, the cult of St Katherine had become of some local importance. This chapter examines how and why Katherine’s cult emerged in Normandy and the way in which it developed down to c.1100. It concludes with an analysis of a small late eleventh-century collection of miracles performed by Katherine’s Rouen relics, which provides some insights into clerical and lay attitudes to the cult. To assist with this analysis I have prepared the first English translation of the text of the miracle collection. 2