Conversion in the medieval Christian context was far from a simple matter. Historians working on the question as it was manifested in Latin Christendom have long recognized that what might appear to be a moment is in fact a process. Though a ceremony such as baptism may provide a clear dividing line between the old faith and the new, examples abound of people who were evidently Christian before they were baptized and of those who retained ties to their prior religion long after the sacrament of initiation. If Christian preachers agreed on the necessity of baptism, they often disagreed on the methodology of catechism and the degree of discipline necessary to pronounce a person or a people "Christian." The problem of conversion can therefore be seen in large part as a problem of "correctness." Much "missionary" activity in the late-antique and early-medieval West was therefore directed not at "pagans," but at Christians perceived to be undisciplined in their faith and practice; a notable example is Boniface of Mainz, the great eighth-century Carolingian missionary saint. While this rigorist strain of "conversion" methodology has been studied by a handful of scholars, historians have yet to trace the ways in which this notion - that conversion meant not baptism but proper catechism - continued in the High Middle Ages (ca. 1050-1350). Although committed paganism had been eradicated in Europe at this point, a reform movement (often associated with Pope Gregory VII, though it was a much wider phenomenon) emerged that saw resistance to reform not simply as a problem of obedience, but a reiteration of the older problem of "paganism" among the improperly catechized. This discourse of religious deviance was particularly acute on the periphery of Latin Europe. This paper will discuss the relationship between the idea of "reform" and the discourse of conversion by looking at two saints' lives from the mid-twelfth to the early thirteenth centuries, the Life of St. Malachy of Ireland (written by Bernard of Clairvaux) and the anonymous Life of St. William of AEbelholt (Denmark). Situating these figures within the reform movement of the twelfth and thirteenth centuries and the history of the high-medieval periphery, I will explain how each of these holy men was cast as a missionary. Rather than living and working among actual pagans, however, their role was that of "apostles of rigor" whose task was to convert deviant Christians to the gospel of reform.