Feasting and Mobility in Iron Age Ireland: Multi-isotope analysis reveals the vast catchment of Navan Fort, Ulster

Abstract

Navan Fort is an iconic prehistoric Irish ceremonial centre and the legendary capital of Ulster. The fort has produced an exceptional pig-dominated faunal assemblage that also contained a barbary macaque skull. Dating from the 4th to 1st century BC, it is likely to be a ceremonial feasting centre that may have drawn people and their animals from across Ulster and beyond. This study uses a multi-isotope (87Sr/86Sr, δ34S, δ13C, δ15N) approach to identify non-local animals and reconstruct site catchment. New biosphere mapping means that isotope data can be more confidently interpreted and the combination of strontium and sulphur analysis has the potential to estimate origins. In the absence of human remains, fauna provide the best proxy for human movement. Results for the 35 analysed animals are wide-ranging, especially in terms of strontium (0.707–0.715), which has the largest range for an Irish site. Sulphur values are more restricted (13.1‰−17.1‰) but are high in the context of British and Irish data. Results provide clear evidence for animals (and thus people) coming from across Ulster and beyond, demonstrating the site’s wide catchment. Navan Fort was clearly a major ceremonial centre with far-reaching influence and hosted feasts that drew people and animals from afar.

Towards a biologically available strontium isotope baseline for Ireland

“…This isoscape was based on 88 modern plants from 40 distinct locations in Northern Ireland. However, the new data presented here, based on 228 measurements from 140 locations, results in a revised characterisation of 0.7089 ± 0.0006, consistent with the data from Madgwick et al (2019). While the strontium isotope ratios of animals and humans could even out the local variability seen in plants, it is important to characterise this variability to evaluate the variation that can be expected for a particular "local" animal or human population (see Snoeck et al, 2016;Fernández-Crespo et al, 2020).…”

“…We also recommend that for each study, plants growing near sites of interest need to be sampled and measured to properly characterise the biologically available strontium at the site with a particular focus on plants consumed by animals and humans. This was highlighted by Madgwick et al (2019) who measured plant samples around Navan Fort, Co. Armagh, to provide a local baseline for their Iron Age faunal data. They noted that their results (0.7084-0.7096; n = 7) fell below the range of 0.7099 to 0.7137 previously proposed for the geological formation on which Navan is located (Snoeck et al, 2016).…”

The dietary impact of the Norman Conquest: A multiproxy archaeological investigation of Oxford, UK

“…In contrast, pre-Conquest pigs have comparable δ 15 N values to caprines and cattle. These data suggest that pre-Conquest pigs were largely herbivorous, but with a varied diet suggesting diverse management regimes, and with animals potentially sourced from a wide hinterland with diverse baseline ecosystem isotope signals [36,37]. That some pigs had higher δ 13 C values would be consistent with the exploitation of seasonal pannage [36,38,39].…”

A veritable confusion: use and abuse of isotope analysis in archaeology

“…It has become an increasingly useful provenancing tool in multi-isotope strategies (e.g. Lamb et al 2012;Madgwick et al 2013Madgwick et al , 2019cNehlich et al 2014;Parker Pearson et al 2019;Smits et al 2010;Towers et al 2011;Worley et al 2019).…”