London’s volcanic winter

5 mins read

Mass graves were needed all too often in the Medieval world, but establishing the specific tragedy behind any given set is difficult. Now Don Walker believes that a group in Spitalfields cemetery can be linked to a massive volcanic eruption, as he told Matthew Symonds.

The destructive force unleashed by Vesuvius, Krakatoa and Mount St Helens made those volcanoes household names. Yet all three are dwarfed by the largest eruption of the last millennium. Probably occurring in early 1258 AD, it violently ejected between 200 and 600 megatons of sulphate into the Earth’s atmosphere. Around eight times the yield from Krakatoa, this was an eruption on a cataclysmic scale.

Despite its magnitude, the identity of the volcano responsible remains a mystery. El Chichón in Mexico, Quilotoa in Ecuador and, most recently, a site in Indonesia have all been named as possible culprits. But while the source of the sulphates remains elusive, the eruption’s fingerprints can be found around the globe. Ice cores from both the northern hemisphere and Antarctica preserve its debris, while a thick layer of ash lies among the sediments in Lake Malawi, nestled between Mozambique and Tanzania. Traces can even be found in the records of contemporary chroniclers writing far from the tropics.

A blast from the past: In CA 117 Colin Burgess wrote for us about past volcanic disasters. Read more here


The unseasonableness of the atmosphere

Wherever the volcano lay, Matthew Paris was living thousands of miles away when it blew. A Benedictine monk writing in St Albans abbey, his  Historia Anglorum  covers the period from 1250-59, and intersperses commentary on contemporary events with observations on that most British of obsessions: the weather. Paris was perplexed and troubled by what he saw in 1258. The year got off to a bad start, with the monk recording  such unendurable cold, that it bound up the face of the earth, sorely afflicted the poor, suspended all cultivation, and killed the young of the cattle. But that was just the beginning. As the year progressed the situation deteriorated and it was not long before Paris had cause to put pen to parchment once more. By midsummer he could write that:

when April, May, and the principal part of June, had passed, and scarcely were there visible any of the small and rare plants, or any shooting buds of flowers; and, in consequence, but small hopes were entertained of the fruit crops. Owing to the scarcity of wheat, a very large number of poor people died; and dead bodies were found in all directions, swollen and livid, lying by fives and sixe’s in pigsties, on dunghills, and in the muddy streets… When several corpses were found, large and spacious holes were dug in the cemeteries, and a great many bodies were laid in them together.

Although he could not have known it, Paris’ account is likely to be eye-witness testimony of the devastating fallout of the 1258 eruption. The sheer quantity of aerosols forced into the atmosphere would have been sufficient to create a phenomenon known as a ‘dry fog’. Weakening sunlight and increasing rainfall, it formed a volcanic veil that shrouded the world, blighting crops and leaving thousands starving. Now, Don Walker of Museum of London Archaeology (MOLA) believes that some of the emergency ‘large and spacious holes’ Paris described being dug have been detected in London’s Spitalfields cemetery. For the first time the human cost of the last millennium’s largest eruption has become archaeologically visible.

St Mary without Bishopsgate
The Medieval cemetery at Spitalfields is probably the largest excavated graveyard in the world. Work by MOLA between 1998 and 2001 unearthed a staggering 10,516 burials, of which just over 5,300 have been studied in detail. Allowing for those portions of the cemetery destroyed during the construction of Spitalfields market, it is probable that around 18,000 people were once interred there. As well as providing an unparalleled corpus of skeletal material for the period, a rigorous programme of Bayesian radiocarbon dating (see  CA  259) by Alex Bayliss and Jane Sidell has provided a tight chronology for the Medieval cemetery. Securing detailed phasing for a site type that is notoriously hard to date proved crucial when it came to understanding how the cemetery population met their fate. It also allowed change within that population to be studied over time, providing vivid insights into the evolving nature of London life.

Spitalfields cemetery was closely associated with the priory and hospital of St Mary without Bishopsgate, later known as St Mary Spital. Claimed to be the largest hospital in London when it was closed during the Dissolution in 1539, the institution was originally founded in around 1197. Intended to minister to the poor, sick and infirm, as well as women in childbirth, the new establishment was a reaction to the care needs of London’s growing population.

Read Colin Burgess’ thoughts on the impact of volcanos on population – from our disasters special in CA 117


The first burials in the cemetery, however, seem to have been a response to pressures of a different kind. Radiocarbon dated to about 1120, the earliest bodies pre-date the priory by a good 70 years. Far from occupying ordered rows, the corpses were dumped in open quarry pits. Such opportunistic interment away from any known religious house evokes an emergency situation in which large numbers of bodies needed to be disposed of rapidly. If so, it was not the last time that a catastrophe heralded the suspension of normal burial practices at Spitalfields.

The foundation of St Mary Spital brought the construction of a priory church at the north-west corner of the cemetery, while the other buildings were clustered nearby. Although the majority of those laid to rest in the graveyard were placed in individual grave shafts sunk in neat rows, excavations revealed a group of 140 large pits clustered along the south and east margins of the burial ground.

Dug as far from the priory buildings as the cemetery confines allowed, each pit contained between 8 and 40 bodies. A sure sign that the death rate had once again outstripped existing burial measures, the desire to keep these mass graves away from inhabited areas underscores a very real fear of the dangers the bodies could pose for the living. In London, as elsewhere, the natural reaction to discovering such mass burials is to interpret them as plague pits from the 1348 Black Death.

Mike Baillie wrote for us on how tree rings can reveal past disasters – full story in  CA 117


Radiocarbon analysis dealt a fatal blow to this notion, however. Consistently returning dates around the mid 13th  century for both sets of burials, this placed them almost a century too early for the Black Death. It was this hard chronological information that allowed Don Walker and Amy Gray Jones of the University of Chester to make a connection between the later group of mass burials and the widespread fatalities seemingly brought on by climatic fluctuation in the wake of the 1258 eruption.

The earlier pits would fit reports of a famine in 1252. The difference in severity appears to have been marked — while the first mass graves typically contain between 8 and 20 bodies, the second group were larger and held 20-40, implying that up to twice as many corpses needed disposing of at any given moment. Between them the two pit groups contained 2,323 people from the studied sample, accounting for over half the analysed bodies buried in the cemetery during this period. Study of the skeletons provides a potent snapshot of life in the capital on the eve of the 1258 eruption.

This is an extract, but the full article can be read in  CA  270.

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