The High-Status Late Medieval Skull Shaped Relic in Turku Cathedral, Finland – a study of its origin with oxygen and strontium isotope analyses

The relics and associated reliquaries of Turku Cathedral are among the most significant early Christian artefacts in Finland preserved in situ. Despite their importance, they have not been the focus of scientific enquiry for a number of decades. This study has focused on one skull shaped relic, although the origin and name of its associated saint remains unknown. The relic is the only such example with high-status decoration in the Turku Cathedral collection and is covered with a red silk decorated with yellow yarn. The bones and fabric have been dated from the beginning of the modern era to the 13th century AD, and variance among the radiocarbon (14C) dates acquired from the bones shows the remains incorporate several individuals. In this study, oxygen and strontium isotope compositions were determined from fragmented bones and textiles. The results are the first isotope analysis performed on this collection housed in Turku Cathedral. Analysis indicates an origin from outside Finland, possibly elsewhere in northern Europe or an Alpine region. This helps take us a little closer to understanding the mystery associated with this sacred artefact.