This new section aims to highlight the latest goings-on in the world of archaeological science. In the future, Science Notes will cover everything from in-depth analysis of breaking news, to advancements in scientific techniques, to highlighting specific laboratories and units.
A drawing of the original plan of grave Bj 581, a burial in Birka, Sweden whose female occupant was laid to rest with grave goods including numerous weapons and the remains of two horses. (Image: Hjalmar Stolpe)
For our first Science Notes outing, we bring you a recently published paper that has caused a bit of a stir in the archaeological world, as it claims to have identified a female Viking warrior. While the burial in question is from Birka in Sweden, not the British Isles, we are covering it because the finding could have major implications for our perceptions of the greater Viking world, and it is also a good place to start in terms of discussing archaeological science, simply for the sheer number of techniques used: osteological, genomic, and isotopic analysis.
First discovered in the 1870s, grave Bj 581 – one of more than 1,100 burials excavated in Birka – was found to contain a plethora of war-related grave goods, including a sword, an axe, a spear, armour-piercing arrows, a battle knife, two shields, and the remains of two horses. Taken together, the artefacts seemed to indicate a Viking warrior, and the individual was originally assumed to be male. More recently, though, macroscopic analysis of the bones themselves indicated that the individual was probably female. This proved a controversial finding for some academics, despite depictions of women warriors in Viking-era art and poetry. So how was this identification established?
Osteologists determine the sex of skeletal remains based on changes to our bones that occur due to the increased production of sex hormones during puberty. Primarily, testosterone causes the skull and pelvis to become more robust in males, and oestrogen contributes to the widening of the hips in females. Analysis using this technique has a fairly high success rate, but in this case it was insufficient to sway some more sceptical observers, and so, to confirm these unexpected osteological results, a group of archaeological scientists decided to carry out ancient DNA (aDNA) analysis on the remains. Samples taken from the left canine and left humerus were analysed at the Archaeological Research Laboratory (AFL) at Stockholm University. There, DNA fragments were assessed for the level of degradation present that would indicate that it was of ancient, and not modern, origin. This is to verify that the extracted DNA was from the skeleton, and not modern contamination. The results were consistent with someone who lacked a Y chromosome and was thus identified as female.
Some of the grave goods from Bj 581.
To determine the woman’s origins and migration history, strontium (Sr) isotope analysis was also carried out on three molars from the individual’s lower jaw (mandibular molars) and compared with several other Birka specimens, as well as samples from elsewhere in the region.
The results showed that Sr values for grave Bj 581 were in the lower range compared to the other individuals buried at Birka and fell outside of the Sr baseline for the region. This suggests that the woman was probably not local and had moved to the area. Additionally, varying Sr values between the first and second mandibular molars also indicated mobility during her early years. This move likely occurred when she was younger than three, when her first permanent mandibular molar would have already formed but the second had yet to appear.
Overall, the study successfully demonstrates that the individual from Birka was biologically female, but sex does not necessarily equate to gender or social identity, and the meaning of her grave goods is still the subject of fierce academic debate. Do the objects indicate a warrior role, or high social status? This research is just the beginning – it opens up a whole range of questions about how gender was conceptualised and structured in the Viking world.
The paper, published in the American Journal of Physical Anthropology, summarises its own impact as showing ‘how the combination of ancient genomics, isotope analyses, and archaeology can contribute to the rewriting of our understanding of social organization concerning gender, mobility, and occupation patterns in past societies.’ It can be accessed for free at https://doi.org/10.1002/ajpa.23308.