The devotional complex of the chapel of Saint-Fiacre in Brittany offers an exceptional opportunity to consider the role of the natural world in the construction of the sacred in the late Middle Ages. Interactions between landscape, architecture, and ritual, this essay argues, created a devotional experience replete with the presence of the natural world. As prominent ecological features and building materials, the ecological phenomena of water and wood were instrumental in the construction of ritual worship at Saint-Fiacre. Spring water flowing from a nearby source and oak wood hewn from the surrounding forest shaped sacred objects in and around the rural healing chapel. The ecological characteristics of healing waters intersected with understandings of the salvific theology of the blood of Christ; the hewn ecology of the oak jubé or rood screen framed the ontological complexity of Christ’s human and divine body on the cross. Through an ecocritical study of the chapel’s healing fountain and its double-sided jubé, this essay examines the persistence of the natural within the sacred.