Аннотация:Archaeological and documentary evidence is used to argue that the superstructure of St Moling’s Well, Co Carlow, is a baptismal chapel of round 1100, probably built in the context of a heightened concern with the proper administration of the sacrament during the Gregorian reform. In earlier centuries, baptism in the open air, at holy wells and springs seems to have been common. Other water-based rituals carried out at St Mullin’s in medieval times are also considered.