A person living in medieval society had to choose a social persona from those that were on offer, and their community had to interpret and accept it. The narratives about saints’ childhood in canonization testimonies usually repeat the topos of puer senex/puella senex, in which holiness manifests itself already in their early years. Sometimes the formation of a persona as a saint was, however, portrayed as a dramatic transformation. The saints either made a complete conversion, or their saintly path faced obstacles or included moments of crisis that defined their future holiness. These moments are among the most dramatic ways infirmity could be used to reconstruct or even create sanctity. There is the trope of a saint converting to a religious life as a result of physical ailment, or being prompted by illness or impairment to change his or her habits and lifestyle. This motif is common in the numerous vitae of saints, but not so commonly depicted in the canonization processes. One reason for this apparent void is that redemption narratives become less popular in the late thirteenth century, at least when it comes to official sanctity. The few examples we have of infirmity leading to the path of sainthood are, nevertheless, worth discussing before moving on to the more common ways infirmities were used in constructing sainthood.