When archeologists began excavating the St Mary Spital site 20 years ago, they expected to find bodies. This had, after all been home to a cemetery almost as old as the capital, as the Romans carried their dead to be buried safely outside the City walls. Then, in 1197 the cemetery had become the site of a priory: the New Hospital of St Mary without Bishopgate, one of the largest hospitals in medieval England.
But as the scientists dug, the skeletons kept on coming. Rather than numbers in the hundreds, or low thousands, the archeologists eventually uncovered 10,500. And with a further part of the cemetery lying unexplored beneath Spitalfields Market, they extrapolated the total number to more than 18,000 – all buried within a very few years. With the total population of London only numbering 50,000 in medieval times, it suggested a cataclysmic event – and one that must have changed London, its population and its economy out of recognition.
Fourteenth century monk, William of Ockham, would have known a little about medieval plague and pestilence. And following his famed dictum, to go for the most likely explanation, it made sense for the archeologists to look first at two of the greatest cataclysms of the Middle Ages. The Black Death had, after all, carried off around half the population of England (anywhere between 3 and 6 million) in 1348. Thirty years earlier, the Great Famine of 1315-17 had seen crop failures, a doubling of grain prices in England and the loss of anywhere between 10 and 25 per cent of the population. Could these two be the killers?
For the scientists, a mass burial pit is a gift. Rather than an orderly medieval burial, with toffs separated from hoi polloi, and men from women, all the corpses were thrown in together, and it gives the perfect cross-section of the London population at the time. The only problem, as carbon dating of the remains progressed, was that the Spitalfield skeletons all seemed to date from around 1250, much too early to have been carried away by the Famine or Plague. Don Walker, an osteologist (bone scientist) working with the Museum of London Archeological team (MOLA) was puzzled. Then he started digging back through the history and found numerous accounts of famine, crop failure and death starting around 1258.
The writings of Benedictine monk Matthew Paris, ensconced in St Albans Abbey a few miles north, were typical. Matthew’s Historia Anglorum is an invaluable historical document and – being British – he was obsessed with the weather. The friar watched in dismay as the harsh winter of 1258 showed no signs of abating. There was “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…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.”
Medieval man lived from year to year, with little in reserve, and soon the death toll began to mount. Matthew continues: “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 sixes 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.”
So there had been a terrible crop failure caused by awful weather – but was it simply bad luck? The people of the time would have put it down to the will of God, punishing Londoners for their sins, but now Don found another clue, uncovering references to a cataclysmic volcano that erupted at this time. Scientists know for certain there was an eruption at the time, though they haven’t yet pinned down the exact source: best guesses include El Chichón in Mexico or Quilotoa in Ecuador. What they do know for sure is that is was huge.
Vulcanologist Bill McGuire, of University College London, puts the 1258 eruption in context, saying: “Volcanoes have a very long reach because they can impact climate. They don’t just affect people nearby.” An Icelandic eruption in 1783 threw a sulphurous cloud over Europe for a year, causing thousands of death. But the effects of ‘Spitalfields volcano’ were far greater. “This was the biggest eruption in historic times. It may have brought the temperatures down by 4°c, a huge amount. And because it was somewhere in the tropics it meant that the winds of both hemispheres could carry these gases right across the planet…gases can spread into both hemispheres and encircle the whole planet in a sulphurous veil.”
It wasn’t the first or last time a volcano would affect London. The 1815 eruption of Mount Tambora in Indonesia is the most powerful in recorded history, lowering global temperatures, leading to worldwide harvest failures and causing “The Year Without a Summer.” Cool temperatures and heavy rains meant failed harvests and the worst European famine of the 19th century. Then in 1883, the explosion of Krakatoa created a four-year winter, with record snowfalls worldwide. But the 1258 explosion appears to be the most devastating of all in its toll of life. It looks like Don Walker has his culprit. “This is the first archaeological evidence for the 1258 volcano and is an excellent example of the complexity of knowledge that can be gained from archaeological evidence,” says Don. “It is amazing to think that such a massive global natural disaster has been identified in a small area of east London.”
On the other side of the world a huge explosion had forced thousands of tons of matter into the atmosphere. A ‘dry fog’ would descend, and right across the planet, the Earth’s surface would begin to cool, and within months the people of a distant city would start to die. The people of 13th century London never knew what hit them.