El 6 de mayo de 2015, la Fundación Ramón Areces celebró una nueva conferencia del ciclo 'Guerras, catástrofes, crisis: lecciones de Historia económica'. En esta ocasión, el profesor Bruce M. S. Campbell, de la Queen’s University, habló sobre 'La Peste Negra del siglo XIV: una reinterpretación'. Este ciclo está organizado en colaboración con el Instituto Figuerola de Historia y Ciencias Sociales de la Universidad Carlos III de Madrid.

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

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.
WORLD NEWS (August 2013):
15-year old herdsman dies of plague in
Krygyzstan.
WORLD NEWS (January 2015):
40 plague deaths in 2014 in
Madagascar!
WORLD NEWS (July 2014):
Chinese city of Yumen sealed off after a mancontracts plague from an infected marmotand dies.

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 pandemics:
AD 541: First Pandemic (Justinianic Plague) –
devastated the Byzantine Empire.
1346: Second Pandemic (Black Death) – spread
throughout the Known World and killed 30%-40%
of a European population of c.80 million (24-
32m.).
1855: Third Pandemic – broke out in Yunnan
Province of China; spread worldwide; the first to
be medically analysed and diagnosed.

4. The impact of the Black Death and its sequel plagues
upon European populations was massive and long
lasting:

5. Economic output also contracted almost everywhere,
as plague killed both producers and consumers:

6. Decades
Indexed GDP per head
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:

7. In England the sudden scarcity of labour triggered the
single greatest inflation in labourers’ daily wage rates
on historical record.

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. Irish
English
Across Europe woodland
regenerated as:
Construction activity
almost ceased.
Farmland was
abandoned.

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

13. PNAS
Proceedings of theNationalAcademyof Sciences
of theUnitedStates of America
November2000, Volume 97, no. 23, 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.
impreciseimprecise
contaminated
contaminated
unrepresentative
unrepresentative
The
firstforensi
c
evidenc
e

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

15. Since 2010 confirmation that the Blackconfirmation that the Black Death
was indeed bubonic plague, i.e.bubonic plague, i.e. Yersinia pestis,
has come from aDNA analysis of dental remains
from datable 14th
-century plague burials in 5
Western European countries:
1.1. France (France (Saint Laurent-de-la-CabrerisseSaint Laurent-de-la-Cabrerisse))
2.2. Italy (Italy (Parma & VeniceParma & Venice))
3.3. Southern Germany (Southern Germany (AugsburgAugsburg))
4.4. The Netherlands (The Netherlands (Bergen op ZoomBergen op Zoom))
5.5. England (England (Hereford and East Smithfield, LondonHereford and East Smithfield, London).).
A Rapid Diagnostic Test has yieldedA Rapid Diagnostic Test has yielded
complementary results.complementary results.
Crucially,Crucially, these aDNA results have been
obtained in separate laboratories by

16. Meanwhile, a 23-strong team of biologists & geneticists
has reconstructed the Yersinia pestis phylogenetic tree:
Giovanna MorelliGiovanna Morelli and 22 others (2010), ‘Yersinia pestis genome
sequencingsequencing 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:
‘PopulationPopulation 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 1st
and 2nd
Pandemics 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 ChinaThe 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-Tibet is oneQinghai-Tibet is one
of several regionsof several regions
where permanentwhere permanent
(enzootic) reservoirs(enzootic) reservoirs
of plague existof plague exist
among ground-among ground-
burrowing andburrowing and
hibernating sylvatichibernating sylvatic
rodents, in this caserodents, in this case
great gerbils :great gerbils :

23. The plagueThe plague
cycle:cycle:
TheThe
transformation oftransformation of
plague from anplague from an
enzootic diseaseenzootic disease
amongamong
maintenancemaintenance
hosts of wild-hosts of wild-
rodents to a fast-rodents to a fast-
spreading andspreading and
deadly humandeadly human
pandemicpandemic
entailed at least

24. The plagueThe plague
cycle:cycle:
Stage 1 –Stage 1 –
enzooticenzootic
plague
1

25. 2
The plagueThe plague
cycle:cycle:
Stage 2 –Stage 2 –
epizooticepizootic
plague

26. 3
The plagueThe plague
cycle:cycle:
Stage 3 –Stage 3 –
panzooticpanzootic
plague

27. 4
The plagueThe plague
cycle:cycle:
Stage 4 –Stage 4 –
ZoonoticZoonotic
Givry (Burgundy),
1348
Penrith (N England),
1597-9

28. 5
The plagueThe plague
cycle:cycle:
Stage 5 –Stage 5 –
PandemicPandemic

29. The plagueThe plague
cycle:cycle:
Historically,Historically,
climaticclimatic
conditions in Aridconditions in Arid
Central Asia haveCentral Asia have
exercised aexercised a
powerfulpowerful
influence uponinfluence upon
the incidence ofthe incidence of
plague, eitherplague, either
lowering orlowering or
raising the risksraising the risks
of enzooticof enzootic
plague becomingplague becoming

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

31. Drought lowered the risks of plague outbreaks byDrought lowered the risks of plague outbreaks by
depressing biomass output, food availability, and gerbildepressing biomass output, food availability, and gerbil
populations and, at the same time, inhibiting flea activity.populations and, at the same time, inhibiting flea activity.
These were the conditions that prevailed in Arid CentralThese were the conditions that prevailed in Arid Central
Asia throughout the Medieval Solar Maximum betweenAsia throughout the Medieval Solar Maximum between
the end of the 1the end of the 1stst
Pandemic in the the 8Pandemic in the the 8thth
century andcentury and
start of the 2start of the 2ndnd
Pandemic in the 14Pandemic in the 14thth
century.century.

32. Drought lowered the risks of plague outbreaks byDrought lowered the risks of plague outbreaks by
depressing biomass output, food availability, and gerbildepressing biomass output, food availability, and gerbil
populations and, at the same time, inhibiting flea activity.populations and, at the same time, inhibiting flea activity.
These were the conditions that prevailed in Arid CentralThese were the conditions that prevailed in Arid Central
Asia throughout the Medieval Solar Maximum betweenAsia throughout the Medieval Solar Maximum between
the end of the 1the end of the 1stst
Pandemic in the the 8Pandemic in the the 8thth
century andcentury and
start of the 2start of the 2ndnd
Pandemic in the 14Pandemic in the 14thth
century.century.
Increasing aridityIncreasing aridity

33. Onset of pluvial conditions increased the risks of plagueOnset of pluvial conditions increased the risks of plague
outbreaks by raising biomass output, food availability,outbreaks by raising biomass output, food availability,
and gerbil populations and, at the same time, stimulatingand gerbil populations and, at the same time, stimulating
flea activity.flea activity.
These were the conditions that prevailed in Arid CentralThese were the conditions that prevailed in Arid Central
Asia following onset of the Wolf Solar Minimum andAsia following onset of the Wolf Solar Minimum and
especially from the 14especially from the 14thth
century as part of a globalcentury as part of a global
reorganization of atmospheric circulation.reorganization of atmospheric circulation.
Increasing
humidity
Increasing
humidity

35. Changes in atmospheric circulation across
inner Eurasia

36. Changes in atmospheric circulation across
inner Eurasia

37. Strong Westerlies
Weak
Westerlies
Changes in atmospheric circulation across
inner Eurasia

38. Parallel changes were taking place in the
strength of the South Asian Monsoon:
Strong monsoon
Weakening
monsoon
Mega
drought

39. Weak
Westerlies
Plague’s reactivation from an enzootic to an epizootic
state sometime after 1268/1282 coincided with an
episode of global climate reorganisation:

40. Dendrochronologies from Central Asia bring this episode
into sharper focus:

41. Dendrochronologies from Central Asia bring this episode
into sharper focus:

42. Dendrochronologies from Central Asia bring this episode
into sharper focus:

43. Dendrochronologies from Central Asia bring this episode
into sharper focus:

44. Ecological stress in Arid Central Asia, generated by increased
climatic instability, appears to have ignited the epizootic that led
to the Black Death.

46. W. EuropeW. Europe
Christakos, Olea &Christakos, Olea &
Hwa-Lung (2007)Hwa-Lung (2007)
c.c.1½-6 kms per day1½-6 kms per day
Qinghai / Tibet?Qinghai / Tibet?
Kipchak Khanate
/ Golden Horde
Kipchak Khanate
/ Golden Horde
Messina, SicilyMessina, Sicily
Issyk-Kul,
Kirghizia
Issyk-Kul,
Kirghizia
13461346
13471347
1338/91338/9
1290s?1290s?
c.40 yearsc.40 years
2,000 kms2,000 kms
c.1 km per weekc.1 km per week
c.7 yearsc.7 years
4,000 kms4,000 kms
c.c.1½ kms per day1½ kms per day
The speed of the Black Death’s spread implies thatThe speed of the Black Death’s spread implies that
humans must in some way have been complicit in itshumans must in some way have been complicit in its
dissemination.dissemination.

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

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

49. “In the same year [1346], God’s punishment struck the people in the
eastern lands, in the town Ornach [on the estuary of the R. Don], and in
Khastorokan, and in Sarai, and
in Bezdeh, and in other towns in those lands; the mortality was great .....
so that they could not bury them”
(Benedictow, 2004)
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 13th
century.
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.

51. The Black Death - some fresh
insights from recent research:
5. Traders and travellers were instrumental
in aiding and abetting plague’s westward
spread across the interior of Eurasia.
6. Genoese mariners performed the same function once
plague reached the Black Sea coast and had crossed
over and infected commensal rodents (i.e. black rats).
7. In Europe, poverty, over crowding, high levels of
commercial activity, war, harvest failure and unusually
humid weather conditions combined to ensure that the
Black Death’s spread was rapid and its mortality heavy.
8. Further changes in plague’s hosts and vectors may
have added momentum and reach to the disease’s

52. The Black Death - some fresh
insights from recent research:
9. The Black Death was the
product of a unique
conjuncture of biological,
climatic and human
developments.

53. The Black Death - some fresh
insights from recent research:
10.The fate of medieval Europeans was
intimately bound up with environ-
mental developments taking place
6,000 kilometres to the east, in the semi-arid and
sparsely populated interior of Central Asia.

54. EL FINEL FIN