New light on the New light on the Black Death Black Death

1. New light on the New light on the Black Death Black Death The plague in Tournai London plague burials Fundación Ramón Areces Bruce M. S. Campbell Professor Professor of Medieval Economic of Medieval Economic History, The Queen’s University of Belfast b.m.campbell@qub.ac.uk History, Y. Pestis phylogenetic tree

2. Today, plague is a global disease with 1,000-2,000 cases a year reported to the World Health Organisation. Plague cases and deaths are both greatest in sub- Saharan Africa.

3. Today, plague is a global disease with 1,000-2,000 cases a year reported to the World Health Organisation. Plague cases and deaths are both greatest in sub- Saharan Africa. Fear of plague derives from history’s 3 great Fear of plague derives from history’s 3 great pandemics: pandemics: AD 541: First Pandemic ( AD 541: First Pandemic (Justinianic Justinianic Plague) the Byzantine Empire. the Byzantine Empire. 1346: Second Pandemic (Black Death) 1346: Second Pandemic (Black Death) – – spread throughout the Known World and killed 30% throughout the Known World and killed 30%- -40% of a European population of c.80 million (24 European population of c.80 million (24- -32m.). 1855: Third Pandemic 1855: Third Pandemic – – broke out in Yunnan Province of broke out in Yunnan Province of China; spread worldwide; the first to be medically China; spread worldwide; the first to be medically analysed analysed and diagnosed. and diagnosed. Plague) – – devastated devastated spread 40% of a 32m.).

4. The impact of the Black Death and its sequel plagues upon European populations was massive and long lasting: 125 100 Indexed population (100 = AD 1300) 75 50 Europe (100 = 79m) England (100 = 4.75m) Italy north-centre (100 = 7.75m) 25 0 1250 1300 1350 1400 1450 1500 Decades

5. Economic output also contracted almost everywhere, as plague killed both producers and consumers: 140 England Italy Indexed GDP (100 = mean 1340s) 120 Spain 100 80 60 40 1300 1350 1400 1450 Quinquennia

6. In terms of GDP per head, loss of numbers proved to be beneficial for England and Holland, a mixed blessing for Italy, and a significant setback for Spain: 175 150 (100 = mean 1310s-1340s) GDP per head 125 100 75 Indexed GDP per head England Spain Italy Holland 50 1300 1350 1400 Decades 1450

7. In England the sudden scarcity of labour triggered the single greatest inflation in labourers’ daily wage rates on historical record. Nominal wages of farm workers as % of previous 31 years (source: Gregory Clark) Black Death 200 175 Napoleonic Wars Tudor price inflation 150 % wage 125 100 75 Reformation 50 1250 1350 1450 1550 Years 1650 1750 1850

8. In Siena work on the vast new nave being added to the cathedral of Santa Maria Assunta was abandoned and never resumed.

9. In Siena work on the vast new nave being added to the cathedral of Santa Maria Assunta was abandoned and never resumed. In neighbouring Florence, work on Giotto’s new Campanile was suspended at the second stage and only resumed after an interval of 10 years.

10. Across Europe woodland regenerated as: 60 PRE-PLAGUE POST-PLAGUE Indexed wage / Cumulative start dates 50 Irish Net cumulative total oaks started Construction activity almost ceased. 40 English 30 Real farm wage rate (5 yr m.a.) 20 Farmland was abandoned. 10 0 1300 1325 1350 1375 -10 REGENERATION DEPLETION

11. Epidemiologically, demographically, environmentally, economically and culturally, the Black Death was a watershed historical event. What disease was it?

12. The list of suspects has The list of suspects has included: included:  bubonic plague bubonic plague (Shrewsbury, 1971, and many (Shrewsbury, 1971, and many others) others)  anthrax anthrax ( (Twigg Twigg, 1984) , 1984)  a v (Scott & Duncan, 2001) (Scott & Duncan, 2001) a viral iral haemorrhagic haemorrhagic fever fever  a now extinct disease a now extinct disease (Cohn, 2002) (Cohn, 2002)  bi biological fallout from ological fallout from an terrestrial impact in Jan. 1348 terrestrial impact in Jan. 1348 (Baillie, 2006) (Baillie, 2006) an extra extra- -  something else entirely something else entirely . . . . . . . . . .

13. PNAS PNAS Proceedings of the National Academy of Sciences Proceedings of the National Academy of Sciences o of the United States of America f the United States of America November November 2000, Volume Volume 97, no. , no. 23, pp. , pp. 12800-12803. . Claimed to have identified the DNA of Yersinia pestis (bubonic plague) in the dental pulp of medieval plague burials at Montpellier in southern France.

14. October 7, 2010 STOP PRESS aDNA analysis proves the Black Death was vector-borne Yersinia Pestis after all!

15. Since 2010 Since 2010 confirmation confirmation that the Black indeed indeed bubonic plague, i.e. bubonic plague, i.e. Yersinia from from aDNA aDNA analysis of dental remains from datable 14 analysis of dental remains from datable 14th century plague burials in 5 Western European countries: century plague burials in 5 Western European countries: that the Black Death was Yersinia pestis pestis, has come Death was , has come th- - 1. 1. France ( France (Saint Laurent-de-la-Cabrerisse) ) 2. 2. Italy ( Italy (Parma & Venice) ) 3. 3. S Southern Germany ( outhern Germany (Augsburg) ) 4. 4. The Netherlands ( The Netherlands (Bergen op Zoom) ) 5. 5. England ( England (Hereford and East Smithfield, London). ). A Rapid Diagnostic Test has yielded complementary A Rapid Diagnostic Test has yielded complementary results. results. Crucially, Crucially, these separate laboratories by independent teams of scientists. separate laboratories by independent teams of scientists. these aDNA aDNA results have been obtained in results have been obtained in

16. Meanwhile, a 23-strong team of biologists & geneticists has reconstructed the Yersinia pestis phylogenetic tree: Giovanna Morelli and 22 others (2010), ‘Yersinia pestis genome sequencing identifies patterns of global phylogenetic diversity’, Nature Genetics 42 (12), 1140-43.

17. This has since been amplified and redefined in a key paper by Yujun Cui and 32 others to show where the Black Death genomes fit in: ‘Population structure of Y. pestis revealed by core genome SNP analysis’, PNAS 110 (2), 2013, 577-82.

18. Genetic reconstruction has yielded the following key conclusions: 1. Y. pestis evolves clonally; small mutations differentiate plague’s different branches (polytomies) and strains. 2. Fresh polytomies are prone to emerge during major epizootics/panzootics. 3. Almost all strains are capable of infecting and killing humans. 4. There is nothing to suggest that the genomes responsible for the Black Death were more dangerous than any others. 5. The 1stand 2ndPandemics arose from different crossovers of the pathogen from animals to humans.

19. Genetic reconstruction has yielded the following key conclusions: 6. The plague genome embodies its own evolutionary history and pattern of spread. 7. Individual strains tend to be country-specific. 8. Regions where plague has existed longest tend to exhibit the greatest genomic diversity and the presence of the earliest genotypes.

20. Genetic reconstruction has yielded the following key conclusions: 6. The plague genome embodies its own evolutionary history and pattern of spread. 7. Individual strains tend to be country-specific. 8. Regions where plague has existed longest tend to exhibit the greatest genomic diversity and the presence of the earliest genotypes. 9. Geographically, the semi-arid Qinghai-Tibet Plateau of Western China appears to have been the ultimate origin of the Black Death. The Qinghai-Tibet Plateau of Western China

21. Genetic reconstruction has yielded the following key conclusions: 6. The plague genome embodies its own evolutionary history and pattern of spread. 7. Individual strains tend to be country-specific. 8. Regions where plague has existed longest tend to exhibit the greatest genomic diversity and the presence of the earliest genotypes. 9. Geographically, the semi-arid Qinghai-Tibet Plateau of Western China appears to have been the ultimate origin of the Black Death. 10.Temporally, the Black Death genome emerged during a biological ‘big bang’ shortly after 1268 (Cui and others, 2013) or 1282 (Bos and others, 2011). c.1268/1282

22. Qinghai Qinghai- -Tibet is one of Tibet is one of several regions where several regions where permanent (enzootic) permanent (enzootic) reservoirs of plague reservoirs of plague exist among ground exist among ground- - burrowing and burrowing and hibernating hibernating sylvatic rodents, in this case rodents, in this case great gerbils : great gerbils : sylvatic

23. The plague cycle: The plague cycle: The transformation The transformation of plague from an of plague from an enzootic disease enzootic disease among maintenance among maintenance hosts of wild hosts of wild- -rodents to a fast to a fast- -spreading spreading and deadly human and deadly human pandemic entailed pandemic entailed at least 4, and at least 4, and possibly 5, stages: possibly 5, stages: rodents

24. 1 The plague cycle: The plague cycle: Stage 1 Stage 1 – – enzootic plague enzootic plague

25. 2 The plague cycle: The plague cycle: Stage 2 Stage 2 – – epizootic plague epizootic plague

26. 3 The plague cycle: The plague cycle: Stage 3 Stage 3 – – panzootic panzootic plague plague

27. 4 350 Givry (Burgundy), 1348 Penrith (N England), 1597-9 300 Number of deaths 250 200 The plague cycle: The plague cycle: Stage 4 Stage 4 – – Zoonotic plague Zoonotic plague 150 100 50 0 A S O N D J F M A M J J A S O N D J F Month

28. 5 The plague cycle: The plague cycle: Stage 5 Stage 5 – – Pandemic plague Pandemic plague

29. The plague cycle: The plague cycle: Historically, climatic Historically, climatic conditions in Arid conditions in Arid Central Asia have Central Asia have exercised a powerful exercised a powerful influence upon the influence upon the incidence of plague, incidence of plague, either lowering or either lowering or raising the risks of raising the risks of enzootic plague enzootic plague becoming amplified becoming amplified into epizootic plague into epizootic plague etc. etc.

30. The Oslo plague team led by Nils Chr. The Oslo plague team led by Nils Chr. Stenseth investigated and established a link between climate, investigated and established a link between climate, gerbil populations, and outbreaks of gerbil populations, and outbreaks of Yersinia water water- -limited steppe grasslands of southern Kazakhstan: limited steppe grasslands of southern Kazakhstan: Stenseth has has Yersinia pestis pestis in the in the

31. Drought lowered the risks of plague outbreaks by depressing biomass output, food availability, and gerbil populations and, at the same time, inhibiting flea activity. Sunspot numbers from dendro Sunspot numbers from dendro Total Solar Irradiance from ice cores Total Solar Irradiance from ice cores Wolf Minimum 1270s-1330s 150 150 1500) (100 = average 1000- -1500) Indexed value Indexed value (100 = average 1000 100 100 Medieval Solar Maximum 1070s- 1260s 50 50 800s 800s 900s 900s 1000s 1000s 1100s 1100s Decades Decades 1200s 1200s 1300s 1300s These were the conditions that prevailed in Arid Central Asia throughout the Medieval Solar Maximum between the end of the 1stPandemic in the the 8thcentury and start of the 2ndPandemic in the 14thcentury.

32. Drought lowered the risks of plague outbreaks by depressing biomass output, food availability, and gerbil populations and, at the same time, inhibiting flea activity. Total Solar Irradiance from ice cores Total Solar Irradiance from ice cores 1.0 1.0 Wolf Minimum 1400 1400 1270s-1330s WETTER > Index WETTER > Increasing aridity 0.5 0.5 < DRIER Index 0.0 0.0 900 900 1000 1000 1100 1100 1200 1200 1300 1300 < DRIER -0.5 -0.5 Arid Central Asia moisture index Arid Central Asia moisture index Decades Decades 800s 800s -1.0 -1.0 These were the conditions that prevailed in Arid Central Asia throughout the Medieval Solar Maximum between the end of the 1stPandemic in the the 8thcentury and start of the 2ndPandemic in the 14thcentury.

33. Onset of pluvial conditions increased the risks of plague outbreaks by raising biomass output, food availability, and gerbil populations and, at the same time, stimulating flea activity. 1.0 1.0 Total Solar Irradiance from ice cores Total Solar Irradiance from ice cores Wolf Minimum 1400 1400 Increasing humidity 1270s-1330s WETTER > Index WETTER > 0.5 0.5 < DRIER Index 0.0 0.0 900 900 1000 1000 1100 1100 1200 1200 1300 1300 < DRIER -0.5 -0.5 Arid Central Asia moisture index Arid Central Asia moisture index Decades Decades 800s 800s -1.0 -1.0 These were the conditions that prevailed in Arid Central Asia following onset of the Wolf Solar Minimum and especially from the 14thcentury as part of a global reorganization of atmospheric circulation.

34. 1.0 < DRIER Moisture/Precipitation index WETTER > 0.5 0.0 900 1000 1100 1200 1300 1400 -0.5 -1.0 Decades

35. Changes in atmospheric circulation across inner Eurasia Arid Central Asia moisture index Morocco precipitation index Scotland precipitation index 1.0 < DRIER Moisture/Precipitation index WETTER > 0.5 0.0 900 1000 1100 1200 1300 1400 -0.5 -1.0 Decades

36. Changes in atmospheric circulation across inner Eurasia Arid Central Asia moisture index Morocco precipitation index Scotland precipitation index 1.0 < DRIER Moisture/Precipitation index WETTER > 0.5 0.0 900 1000 1100 1200 1300 1400 -0.5 -1.0 Decades

37. Changes in atmospheric circulation across inner Eurasia Arid Central Asia moisture index Morocco precipitation index Scotland precipitation index 1.0 < DRIER Moisture/Precipitation index WETTER > 0.5 Strong Wester lies 0.0 900 1000 1100 1200 1300 1400 Weak Westerlies -0.5 -1.0 Decades

38. Parallel changes were taking place in the strength of the South Asian Monsoon: 1.00 Precipitation index WETTER > Weakening monsoon 0.50 Mega drought 0.00 800 850 900 950 1000 1050 1100 1150 1200 1250 1300 1350 1280s drought Strong monsoon -0.50 < DRIER Oort Solar Min. Wolf Solar Minimum Medieval Solar Maximum -1.00 Decades

39. Plague’s reactivation from an enzootic to an epizootic state sometime after 1268/1282 coincided with an Arid Central Asia moisture index episode of global climate reorganisation: Morocco precipitation index Scotland precipitation index 1.0 < DRIER Moisture/Precipitation index WETTER > 0.5 0.0 900 900 1000 1000 1100 1100 1200 1200 1300 1300 1400 1400 Weak Westerlies -0.5 -1.0 Decades

40. Dendrochronologies from Central Asia bring this episode into sharper focus: Mongolia (Siberian pine) Tien Shan (Juniper ) NE Tibet (Juniper) 150 (100 = mean 1150-1349) Indexed ring width 125 100 75 50 1250 1270 1290 1310 1330 Years

41. Dendrochronologies from Central Asia bring this episode into sharper focus: Mongolia (Siberian pine) Tien Shan (Juniper ) NE Tibet (Juniper) 150 (100 = mean 1150-1349) Indexed ring width 125 100 75 50 1250 1270 1290 1310 1330 Years

42. Dendrochronologies from Central Asia bring this episode into sharper focus: Mongolia (Siberian pine) Tien Shan (Juniper ) NE Tibet (Juniper) 150 (100 = mean 1150-1349) Indexed ring width 125 100 75 50 1250 1270 1290 1310 1330 Years

43. Dendrochronologies from Central Asia bring this episode into sharper focus: Mongolia (Siberian pine) Tien Shan (Juniper ) NE Tibet (Juniper) Mean chronology 150 (100 = mean 1150-1349) Indexed ring width 125 100 75 50 1250 1270 1290 1310 1330 Years

44. Ecological stress in Arid Central Asia, generated by increased climatic instability, appears to have ignited the epizootic that led to the Black Death. Mongolia (Siberian pine) Tien Shan (Juniper ) D R O U G H T T NE Tibet (Juniper) Mean chronology 150 D R O U G H D R O U G H T (100 = mean 1150-1349) Indexed ring width 125 100 P L U V I A L P L U V I A L 75 50 1250 1270 1290 1310 1330 Years

45. From its source in Qinghai, as aridity eased, plague From its source in Qinghai, as aridity eased, plague then spread westwards across desert and mountains then spread westwards across desert and mountains to Issyk to Issyk- -Kul in Kirgizia: Kul in Kirgizia:

46. From its source in Qinghai, as aridity eased, plague From its source in Qinghai, as aridity eased, plague then spread westwards across desert and mountains then spread westwards across desert and mountains to Issyk to Issyk- -Kul in Kirgizia: Kul in Kirgizia: Issyk Issyk- -Kul, Kirghizia Kul, Kirghizia Qinghai / Tibet? Qinghai / Tibet? W. Europe Christakos, Olea & Hwa-Lung (2007) c.1½-6 kms per day c.40 years 2,000 kms c.1 km per week 1346 Messina, Sicily Messina, Sicily 1338/9 1347 1290s? c.7 years 4,000 kms c.1½ kms per day Kipchak Kipchak Khanate / Khanate / Golden Horde Golden Horde The speed of the Black Death’s spread implies that humans must in some way have been complicit in its dissemination.

47. The Catalan World Atlas, 1375: “the intensification of over “the intensification of over- -land caravan movement across Asia that reached its climax under the Mongol across Asia that reached its climax under the Mongol empires ..... affected both macro empires ..... affected both macro- - and micro patterns in far patterns in far- -reaching ways” reaching ways” land caravan movement and micro- -parasitic parasitic

48. The World-system of commerce c.1300 according to Janet Abu-Lughod, 1989. Traders and travellers were material to the relentless westward spread of the pathogen, its vectors and hosts, until the Genoese port of Kaffa in the Crimea was reached in 1346.

49. “In “In the same year [1346], God’s punishment struck the people in the eastern lands, in the same year [1346], God’s punishment struck the people in the eastern lands, in the town the town Ornach Ornach [on the estuary of the [on the estuary of the R R. Don], and in . Don], and in Khastorokan in in Bezdeh Bezdeh, and in other towns in those lands; the mortality was great ..... so that they , and in other towns in those lands; the mortality was great ..... so that they could not bury could not bury them” them” (Benedictow, 2004) Khastorokan, and in Sarai, and , and in Sarai, and Gabriele de Mussis, Michele da Piazza, Nicephoros Gregoras, Emperor John VI & Ibn al-Wardi: Spring 1346: plague first surfaced in the lands of the Kipchak Khanate of the Golden Horde.

50. The Black Death - some fresh insights from recent research: 1. The Black Death WAS Yersinia pestis. 2. Its geographical origin was the semi-arid Qinghai-Tibet Plateau in Western China, where its maintenance hosts were wild gerbils and marmots. 3. Its biological re-activation from a dormant enzootic state to a more virulent epizootic state occurred during the closing decades of the 13thcentury. 4. This vital biological transformation took place under conditions of mounting ecological stress generated by the alternation of drought and pluvial events, as global patterns of atmospheric circulation de-stabilized and changed.