In recent decades, archaeological and written records have been used in combination to improve our understanding of Late Antique and Early Medieval Hispanic architectural culture (5th–10th c.). Within this renewed research context, the rebuilding of Late Antique churches and the reuse of earlier materials in both Early Medieval Christian and Islamic religious buildings; the transformation of Late Antique churches into early Islamic mosques in al-Andalus; and the rebuilding of other churches by the Christians themselves, both in al-Andalus and in the northern Iberian plateau, from the late 8th century onwards, have often been used to thread narratives concerning tradition, continuity, and re-sacralisation of earlier religious architectural spaces and, through this, religious change in the middle ages. However, the application of modern archaeological methodology reveals that these processes need to be qualified, for the stratigraphic gaps between building phases make them sometimes hard to interpret. By analysing some examples of Hispanic religious sites, this paper reflects on the many concepts related to sacralisation, explains the way archaeology is able to trace the sacralisation processes, and intends thus to highlight the complexity of these phenomena.