Dating the bones
Our understanding of the chronology of the charnel chapel has always been problematic. The most secure dating evidence available comes from the architecture of the chapel itself - the south wall of the charnel chapel aligns with the south wall of the church, which was rebuilt around the end of the 13th century. Moreover, there are architectural features in the design of the room that are consistent with this date.
But it is not secure to assume that the date of the room is the same as either the date(s) during which bones were placed in the ossuary, or indeed the period during which the people from which the bones derived were living.
Radiocarbon dating allows us to date the bones directly, providing an indication of when the person was alive.
What is radiocarbon dating?
Radiocarbon dating is a technique that quantifies the amount of radioactive carbon-14 in any organic object. The carbon in our skeletons is obtained from the food we eat, and incorporated into bone tissue as we grow and repair our skeletons. When we die, the radioactive carbon begins to decay at a steady rate, gradually converting into other elements, but the non-radioactive carbon does not decay. Therefore, it is possible to calculate how long ago an organism lived based on the relative amounts of radioactive carbon-14 and non-radioactive carbon remaining in their bones.
No one had attempted to radiocarbon date the bones at Rothwell before. This was largely because it was assumed they were too poorly preserved to successfully date. However, the latest scientific methods require much less carbon to have preserved, opening up the possibility of dating badly degraded bone.
During the summer of 2016 five new radiocarbon dates from the human bones housed in Rothwell Charnel Chapel were obtained. The dates, produced in collaboration with the ¹⁴CHRONO lab at Queens University Belfast, were obtained from five crania.
Three crania provided dates from the late 13th to early 15th centuries, suggesting these individuals lived during the period between c. AD 1250 and 1450. One of these medieval crania has osteological evidence for perimortem trauma in the form of multiple radiating fractures, which indicates they died from a blow to the head. It has long been believed that the bones come from soldiers killed during battle, but we have only found this one example for traumatic injury. Moreover, the bones in the ossuary belong to men, women and children so are unlikely to be a military group.
One of the crania radiocarbon-dated to the 13th to 15th centuries.
Two crania provided dates from the 18th and 19th centuries and could be as little as a century old. One of these crania shows evidence for anatomisation, likely from an autopsy, which also points to a post-medieval date. Two of the five samples providing such recent dates was unexpected.
One of the crania radiocarbon-dated to the 18th to 19th centuries. This cranium also has evidence of autopsy.
What do the dates tell us?
The dating evidence helps refine the chronology of the site, and allows us to more confidently evaluate the various theories about the origins of the bones and role of the chapel. One theory suggests the bones were gathered prior to the building of the room, which was undertaken simply to provide a place for storage. Our dates suggest otherwise. The people we dated lived during the period of use of the charnel chapel, not before.
The long sequence of dates we have obtained, spanning over 700 years, indicates a long-term engagement with the site. Human remains were deposited across the entire medieval period until the site’s closure during the Reformation, and then further bones were added after the supposed 18th-century rediscovery of the site.
In the future, research will need to focus not only on medieval religious practice to explore how the site functioned but also on how more recent people have perceived, and engaged with, the charnel chapel. During the medieval period, we believe the site provided a place in which prayers for the souls of the dead could be said in the physical presence of their bones, but how did this purpose evolve over time?
The radiocarbon dating evidence was first presented to local people at the Rothwell Charnel Chapel Project’s annual Open Day on Saturday 6 August and has been reported by BBC news and radio.
The radiocarbon dating was funded by the Department of Archaeology, University of Sheffield.