During the Later Middle Ages, several crosses and crucifixes in Norway were believed to be wonderworking. Contrary to authoritative theology, they were understood to transgress the purely representational: these objects were treated as if they were the very thing they represented, understood as agents capable of influencing and altering the life of the pious. The crucifixes from Fana and Røldal and the cross from Borre are the only three still extant that were either explicitly referred to as miraculous and/or were pilgrimage sites. For that reason, these objects have received particular attention in this study. By examining their iconography, formal and stylistic solutions as well as their materiality, this thesis explores the potential for understandings, experiences, and functions of wonderworking crosses and crucifixes. Together with analyses of a wide variety of textual sources, we are able to obtain a better understanding of the agency and power that were once credited to these miraculous objects, not only in late medieval Norway, but also in the subsequent centuries following the Reformation.