Sex identification of a Late Iron Age sword and mirror cist burial from Hillside Farm, Bryher, Isles of Scilly, England

A burial dating to the 1st century BCE was found in 1999 in the Isles of Scilly, south-west England. As well as being the most richly furnished burial in the region, it has grave goods considered to have oppositional gender associations: martial items (sword, shield) plus a bronze mirror. The inability to determine sex from the poorly surviving skeletal remains, using morphological or the available genomic methods at the time of its discovery, has been recognised as a key difficulty in the interpretation of this significant burial for Iron Age studies. Here, we apply high throughput DNA sequencing and analysis of dental enamel peptides to the highly degraded human remains in efforts to determine sex. The former effectively showed that no useable aDNA survived in the remains; the latter identified the sex as female with ca. 96% probability. This demonstrates the value of dental enamel peptide analysis for establishing the sex of ancient remains in circumstances where survival of skeletal remains is marginal and when diagenesis has effectively eliminated aDNA. Understanding symbolism in ancient burial rites, and hence making inferences concerning the social identities of the deceased is very difficult. These difficulties are not resolvable by biomolecular analyses. However, the sex identified from the proteomic work adds to the reconstruction of the biological identity of the interred individual, and helps to provide a firmer basis upon which debates concerning her social identity can be conducted. We discuss the funerary treatment of the interred individual in terms of her possible social persona, especially the meaning of the martial items for her potential role in Iron Age warfare.