Evidence from a five-metre-long sediment core has provided archaeologists from the Universities of Nottingham and Cambridge with the first unbroken timeline of Britain's economic history from the 5th century to the present day.
The cylindrical core of slowly accumulated silts, extracted from a paleochannel of the River Ure at Aldborough, Yorkshire – the Roman town that was the capital of the Brigantian people – reveals the first ever continuous record of metal production, pollution and economic history from a metal-producing locality, spanning over 1,600 years.
In a new paper, published in the journal Antiquity, lead author Christopher Loveluck, Professor of Medieval European Archaeology at the University of Nottingham, and a team led by Cambridge academics – Martin Millett, Emeritus Laurence Professor of Classical Archaeology, and Charles French, Emeritus Professor of Geoarchaeology – reveal the fascinating results of the analyses which linked the metal production evidence to excavations and landscape changes at Aldborough over the last two millennia.
While other previous metal pollution records from antiquity and later have been extracted at distance from their sources – upland peat cores or mountain and polar glaciers – uniquely, the data this time comes from where metals were produced, at the heart of the Roman and medieval Yorkshire lead and iron industry. It provides the first measurable continuous record from a metal-producing centre and region of the early medieval period in northwest Europe.
The results show the value of truly interdisciplinary research, linking evidence from archaeological excavations, textual sources and the unique continuous record of metal production at Aldborough, to overturn some long-held notions of when post-Roman industrial collapse occurred in the early Middle Ages, and to affirm the economic impact on people of documented societal events since the Norman Conquest."
Economic growth beyond end of Roman rule in Britain
The revolutionary insights into the economic history of Britain, contradict previous thought that all industrial scale commodity production collapsed around the end of the Roman period (410AD). The results from Aldborough revealed low levels of lead and iron production in the 4th to the early 5th century, but a large continuous rise in iron – and to a lesser extent, lead smelting through the 5th to mid-6th centuries – with the same ore sources and use of coal as in the Roman period. This evidence shows that there was no immediate post-Roman collapse in metal production in northern Britain
In fact, results show the real economic crisis occurred between c.550 and 600AD at Aldborough. There is no 'smoking gun' evidence as to the cause of this sudden crash in metal production, but textual evidence from the Mediterranean and modern-day France (from the mid-late 6th century) shows that this period saw multiple epidemic waves of bubonic plague, and perhaps smallpox. These findings combined with previous ancient DNA evidence from a mid-6th century cemetery in Cambridgeshire show the bubonic plague was killing people in eastern England from the 540s, and this period marked the point of transformation at Aldborough – not the departure of the Roman Empire from Britain's shores.
9th century Viking settlement and prosperity in Britain
The pollution study also provides stunning results for the Viking Age, with the onset of an economic metal boom. Beginning before the Vikings' arrival, but then continuing through Viking control, by the early 9th century, levels of iron and lead production were happening on a large industrial scale at Aldborough, and the surrounding Yorkshire Dales.
Textual and archaeological sources from England and Continental Europe already suggest that there was a growing focus on domestic economies rather than international trade by that time. Before now it has been difficult to prove it at a macro-scale, but the new results show a boom in raw metal production, between the end of the 8th century and through to the 10th century, revealing regional-level economic growth, which has never been measured beyond single sites before.
The Aldborough findings then go on to show a decline in metal production through the 11th century with renewed large-scale growth in lead and iron production reflected again from the mid-12th to early 13th centuries. Results corroborate annual-written sources for increased Yorkshire and wider British lead production from the 1160s-1220, and comparable pollution increases attributed to Britain for these decades recovered previously from Swedish lakes and from previous Alpine ice-core research from Switzerland.
The Dissolution of the Monasteries
For much of the 14th century, Yorkshire lead pollution was in decline again, so the Aldborough lead record does not record a huge crash in production in the mid-14th century due to the Black Death, merely a less dramatic decline. However, by the 1500s the Yorkshire metal industry had returned with a vengeance and massive production resumed until Henry VIII's Dissolution of the Monasteries from 1536-38. Henry's break with Catholic Rome – leaving him free to divorce Catherine of Aragon and marry Anne Boleyn – meant it became uneconomical to make fresh metal with lead being ripped from Britain's monastic institutions and their assets redistributed.
Professor Millett of the Faculty of Classics, University of Cambridge, said: "This collaborative work which forms part of a long-term project at Aldborough adds a new dimension to our understanding of the history of this important Roman town in the immediately post-Roman period. It has significant implications for our wider understanding of the end of Roman Britain."
Corroboration of the Aldborough metal economy record with textual sources and other pollution records from the 1150s onwards, and with excavated evidence from Aldborough Roman town, allows for confidence in the identification of the hitherto never-seen economic trends from the late Roman period to the Viking Age, changing the narrative on the so-called 'Dark Ages.'
Concentrations of metals and other elements linked to metal-smelting, taken from the cylindrical sediment core, were measured at the British Geological Survey (Keyworth, Nottingham) by Inductively-Coupled-Plasma-Mass Spectroscopy (ICP-MS) along the upper 2-metres of the core, and the core was dated using radiocarbon and optically-stimulated-luminescence (OSL) dates and an age-depth-model.
The research was funded by The British Academy and the University of Cambridge.
