The purpose of this chapter is to identify the site where Roland allegedly attempted to break his sword before his death, mentioned in the Guide for the Traveller at the end of the Codex Calixtinus. The discovery of this location represents the identification of an important martyrial shrine, due to the “popular” canonization of Roland as a martyr against Islam as well as accounting for the significance of Roncesvalles (Roncevaux) as a milestone on the road to Santiago de Compostela. The argument is supported by examination of an unprecedented combination of archaeological evidence, literary studies, and palaeographic research on the origin of the Song of Roland and the Codex Calixtinus as well as collections of documents belonging to the kings and churches related to the subject.