Wheat in early medieval England: an archaeological view

Abstract

What can we learn about cereal farming in early medieval England? While the subject benefits from the emergence a rich written record by the 13th century, documentary evidence is exceedingly scarce – or even absent – for earlier periods. To understand which crops were grown between the 5th and 13th centuries, and which crop husbandry strategies were pursued, we must look to the cereal grains, chaff and weed seeds excavated at hundreds of archaeological sites.


Today, wheat is the most commonly grown cereal crop in the UK – especially in England. Could this pre-eminence date back to the medieval or even Anglo-Saxon period?

Unfortunately, we cannot rely on written records for the answer. Historical evidence for crop husbandry in England between the 5th and 13th centuries is patchy, to say the least. Before the emergence of detailed legal documents in the 13th century, the historian is largely reliant on land charters, the Domesday Book (of 1086), place-names, and stray references in other texts – none of which offers an even coverage of England. The 7th-9th centuries are especially poorly documented, and the 5th-6th centuries not at all.

Fortunately, this extremely patchy historical record can be amply supplemented by archaeological evidence. Archaeologists have excavated hundreds of Anglo-Saxon and medieval settlements across England, with more sites being discovered every year, mostly through the investigative work that precedes building developments. A standard part of modern excavation strategies is the retrieval of ancient plant remains which have been preserved at a settlement: archaeobotanical evidence which, in the main, consists of charred crop deposits. Among the crops of the medieval period, cereals were particularly prone to burning: malting and kiln-drying brought them into close contact with fire, while mills, barns, granaries and ricks could be especially vulnerable to conflagration. As a result, cereal grains, chaff, and their accompanying arable weed seeds were routinely, accidentally burned at settlements which handled cereal harvests and, where combustion was incomplete, these remains have survived in the soil as ‘charred’ plant remains – effectively, carbon skeletons which are resistant to bacterial decay.


Figure 1. Medieval charred wheat grains (microscope photograph by M. McKerracher)

Archaeobotanists study these charred plant remains under a microscope, identifying the various species represented by the grains, chaff and weed seeds, and counting how many of each item are present in a soil sample. In this way, it has long been established that the four main documented crops of later medieval England also dominated the farmlands of the 5th-13th centuries: wheat (mostly probably bread wheat: Triticum aestivum), hulled barley (Hordeum vulgare), rye (Secale cereale), and oats (mostly probably common oats: Avena sativa). The story is very much one of free-threshing cereals. There is currently little evidence that spelt wheat (Triticum spelta), the staple wheat crop of Roman Britain, retained any widespread importance after the 4th century – although, as with emmer wheat (Triticum dicoccum), some localised pockets of cultivation seem to have persisted.


The archaeobotanist’s workplace: microscope, petri dishes, and charred plant remains (photograph by M. McKerracher)

The charred plant remains from Anglo-Saxon and medieval England are overwhelmingly dominated by cereal grains and the seeds of arable weeds which were accidentally harvested along with the crop. These weed seeds can offer us valuable insights into the arable environments of the period, since different kinds of weed thrive under different conditions – essentially, the ecological niches produced by different crop husbandry strategies. But in this blog post, we will focus on the cereal remains, and the fundamental questions of whether, where and when wheat became a pre-eminent cereal crop. The results shown below are from the on-going ‘Feeding Anglo-Saxon England’ project at the Universities of Oxford and Leicester (https://feedsax.arch.ox.ac.uk).

The first way of approaching this problem is called ‘presence analysis’: calculating the percentage of archaeological sites at which a given cereal has been identified, for a given period in the past. This gives some measure of a crop’s ubiquity across England, over time, according to the archaeobotanical record. Here we compare the results for the two most ubiquitous crops, wheat and barley. It is immediately apparent that, although both crops remain widespread (present at more than 70% of sites in every period), barley is more ubiquitous than wheat throughout the 5th-13th centuries.


Presence analysis of barley and wheat (charred plant remains) across England, AD 420-1300 (graph by M. McKerracher/FeedSax project)

However, a caveat must be applied: this analysis measures only presence, not abundance: a site with only one barley grain counts for as much as a site with 3,000 barley grains. As a result, it tells us little about the relative contributions of these crops to local yields at individual sites. To address this problem, we can analyse the relative proportions of cereal grains within individual archaeobotanical samples: that is, out of the total cereal grains in each sample, we may calculate the percentage identified as wheat. In the analysis shown below, in order to make the patterns more easily visible, I have included only the three periods with the most archaeobotanical samples, spanning the late 7th to early 13th centuries. From these results it appears that, at a national level, there is no general increase in the relative abundance of wheat grains over these periods.


Percentage of wheat grains in archaeobotanical samples, grouped by period. Each bar is an individual sample (n = 836) (graph by M. McKerracher/FeedSax project)


But could this national, diachronic picture be obscuring inter-regional patterns? To explore this possibility, we can use these same ‘relative abundance’ data (but now including samples from all periods, as we are not looking for diachronic changes) in a geographic analysis called Inverse Distance Weighting. This approach produces a ‘heatmap’ where darker shading indicates higher percentages of wheat grains, and lighter shading indicates lower percentages (white is zero, black is 100%).


Interpolated heatmap of percentages of wheat grains in samples of all periods (n = 1,414) (map by M. McKerracher/FeedSax project, using Ordnance Survey Open Data under the Open Government Licence)

Plotting the data in this way produces a striking pattern: the samples richest in wheat grains seem to be concentrated in a broad, southwest-to-northeast ‘wheat belt’ across central England, with a small eastward spread. This area corresponds very well with the main distribution of clayey soils in England – the very terrains upon which bread wheat is thought best to thrive. There are good reasons for thinking, therefore, that while the Anglo-Saxon and medieval periods did not witness wheat’s rise to national predominance, they did witness the development of an environmentally-based, regional specialisation in wheat farming. In other words, the eventual pre-eminence of wheat seems to have begun in the rich clay vales of central England.



Dr Mark McKerracher Post-doctoral researcher, University of Oxford Institute of Archaeology, 36 Beaumont Street, Oxford mark.mckerracher@arch.ox.ac.uk