After the Calamity: Unexpected Effects of Epidemics on War

Lazar Berman and Jennifer Tischler


The COVID-19 pandemic is a novel event. It shut the world down as leading economies lay dormant and citizens stayed home for weeks on end. But pandemics have been shaping history for millennia. Ancient populations also quarantined, had their lives disrupted, and raged against authorities as deadly diseases ravaged their communities.

As the world emerges from the pandemic, states will return to commerce, diplomacy, and war. Pre-existing rivalries will not disappear. However, many countries and non-state actors will emerge fundamentally changed, as will the dynamics between them.

As military and political leaders try to make sense of how the coronavirus has altered relations with hostile actors, they can draw important insights from past epidemics and their effects on persistent conflicts throughout history. This article examines past epidemics, from the Peloponnesian War in 430 BCE through the modern era, to extract lessons on incentives for aggression, power balancing, alliances, and internal legitimacy. By studying the past, contemporary decision-makers will be better equipped to anticipate challenges and avoid recurring dangers in the wake of pandemics. 

Lessons from Past Epidemics

Disease weakens states and their ability to project military power. However, epidemics have also spurred stricken societies to military action, making them more aggressive in the short term.

In 430 BCE, Athens was in year two of the Second Peloponnesian War against Sparta and its allies. Athenian leader Pericles gathered the population behind the Long Walls while the Spartans ravaged the countryside. A ghastly plague reached the port of Athens and then swept through the crowded city. At the height of the outbreak, Pericles sent a large expeditionary force—four thousand hoplites and three hundred cavalry––to raid the Peloponnesian coast. Why would he order a major amphibious operation while his city disintegrated from within and Spartans destroyed their fields? Pericles believed an offensive would likely lift Athenian spirits and, perhaps more importantly, protect a major part of its combat power by removing it from the diseased city.[1]

“Plague in an Ancient City” by Michiel Sweerts (Wikimedia)

The Iroquois Confederacy—five tribes in modern New York State—traditionally fought what scholars call mourning wars. After losses in battle, Iroquois raiding parties would set out in search of captives. While some captives were ritually tortured, many were adopted into the tribe to replace the fallen warriors: "A father who has lost his son adopts a young prisoner in his place. An orphan takes a father or mother; a widow a husband.“[2] On a societal level, mourning wars served to maintain population numbers; on a familial level, they assured the physical and spiritual continuity of clans; and they helped individuals deal emotionally with loss.[3]

The Iroquois were hit by smallpox and influenza, which likely arrived before they had ever seen Europeans. By the early 1640s, roughly half the Iroquois were dead.[4] Smallpox struck the Mohawk in 1647, the Onondaga in 1656-7, the Oneida, Onondaga, Cayuga, and Seneca in 1661-1663 and again in 1668.[5] The Seneca were also ravaged by influenza in 1676.[6] The Iroquois found themselves in a violent cycle. Disease led to more mourning wars, which were now deadlier with the introduction of muskets. The need to acquire guns further increased the importance of beaver furs, which resulted in wars with French-allied tribes. Deaths in these conflicts led to more mourning wars.[7]

On the northern Plains, smallpox moved up from Mexico in the 1780s and wiped out up to half the population of semi-sedentary tribes on the upper Missouri River, including the Arikara.[8] The nomadic western Sioux tribes were barely touched and came to dominate their stricken neighbors. But as the Arikara huddled into what were effectively refugee camps with survivors from other tribes, some chiefs led attacks solely for the purpose of proving themselves and gaining new followers.[9]

Native Americans and the Smallpox Epidemic (DeWerWeld)

Despite the evidence of short-term aggressiveness, in the long run, epidemics sap the will of societies to fight. Though Pericles was initially adventurous in 430 BCE, Athenian pluck did not last the summer. Patience with Pericles wore thin. Athenians eager to make peace with Sparta sent emissaries to try to find a way out of the war. Unfortunately for Athens, the effort failed. The fighting spirit of Athens remained dampened for years. In 428, the island of Lesbos revolted. Athens, which in the past crushed similar rebellions, looked for reasons not to act.[10] Only when diplomatic efforts were exhausted did it besiege the Lesbian city Mytilene.

In July 1914, in the opening act of the First World War, Austria-Hungary invaded Serbia. Despite initial Serbian successes, it lost Belgrade in November as civilians fled south. Typhus began to appear and quickly spread among these refugees.[11] The epidemic swept rapidly through the country via the movement of refugees and soldiers. Within six months, one in five Serbs had developed typhus, with the overall mortality rate at 20%. Serbia was quickly overwhelmed—its few hospitals were filled and 126 of the country’s 400 doctors died of the disease.[12]

Typhus left Serbia unable to defend itself; killing 70,000 in the military alone.[13] Renewed Austro-Hungarian offensives from October 1915, combined with Bulgaria’s entrance into the war, put Serbia in a perilous position. Typhus and combat casualties reduced its army from 300,000 men at the start of the war to 75,000, and half of Serbia fell under Central Powers control.[14]

A Ukrainian family with Typhus in 1921 (Wikimedia)

One might assume that if one side in a conflict—like Austria-Hungary or Sparta—is unaffected by an epidemic, it will strike its weakened opponent, but history shows this is not always the case. Though it did not afflict Sparta, the plague seems to have diminished its desire to fight Athens directly. The Peloponnesians left Attica early in 430 BCE when they heard of the disease and witnessed its horror.[15] In addition, the Spartans invaded Attica every year from 431-425 BCE, except for 429 and 426 BCE. Both of those years followed major outbreaks of the plague.[16] Sparta could have pressed its advantage while Athens tended to its sick and dying, but its leaders chose to avoid it entirely. Austria-Hungary behaved similarly. Despite declaring war on Serbia in July 1914, it did not invade again until late 1915. Having seen the devastating impact of typhus on Serbia, Austro-Hungarian commanders were loath to expose their armies to the disease. By waiting, Austria-Hungary lost an opportunity to tip the balance of power towards the Central Powers.[17]

Stricken countries like Serbia are badly weakened in the long-term but are not helpless. History shows that these actors often seek new allies to help offset the dangerous erosion in national power. In the winter of 1621, Massasoit, a sachem from the Wampanoag confederacy in what is today southeastern Massachusetts, concluded a peace agreement with the Pilgrims in Plymouth. Massasoit did not negotiate with the settlers because he was afraid of them.[18] Sick and desperate, only about fifty had survived the winter. They did provide access to guns, which was probably less important than many assume. Massasoit was likely embarking on a complex and risky political endeavor in the wake of a cataclysmic plague.

The epidemic ravaging the Wampanoag confederacy reached its peak in 1617, and lasted until 1619. It is not clear what it was, but the plague killed most of the native population from Boston Harbor to Plymouth. A contemporary chronicler wrote, “Thousands of men have lived there, which died in a great plague not long since.”[19] By 1621, Massasoit ruled a devastated confederation. Even worse for the Wampanoag, the plague did not reach the Narragansett, their bitter rivals to the west.

Massasoit therefore viewed the Pilgrims in the context of the now perilous power imbalance with the Narragansett. The alliance could deter the Wampanoags’ rivals in two ways. The Narragansett did not necessarily know of the settlers’ pitiful state, and the pact could make Massasoit seem more powerful than he was. The Narragansetts also benefited greatly from their position as middlemen between English traders and other tribes. Massasoit may well have calculated the Narragansett would not want to risk their economic position by attacking allies of an English settlement.[20]

"The First Thanksgiving at Plymouth" by Jennie A. Brownscombe. How do plague and disease ask us to reexamine this narrative? (Wikimedia)

The semi-sedentary northern Plains tribes—the Mandan, Hidatsa, and Arikara—were devastated by smallpox starting in the 1780s and looked to a drastic new alliance structure to balance against the Sioux. Initially the Arikara joined the Sioux in attacks on the Mandan and Hidatsa, but soon allied with the latter, moving into consolidated villages for mutual defense. Despite sometimes fatal tensions in these multilingual villages, the three tribes at times managed to put aside differences to fight the Sioux. In 1811, American traders encountered 300 warriors from the three tribes on their way to attack the Sioux.[21]

Epidemics also have profound effects within afflicted societies themselves. In both well-organized states and tribal societies, one of the most pronounced impacts is the populace's rejection of traditional practices and sources of authority.

An epidemic—likely the bubonic plague—swept through the Byzantine Empire during Justinian’s reign. It arrived from Egypt in 541 and afflicted the empire sporadically until 750.[22] The emperor himself contracted and survived Justinian’s Plague, which killed approximately 50-60% of the capital and 30% of the empire.[23]

Justinian’s Plague completely disrupted everyday life in Constantinople. All business in the city ceased, craftsmen refused to work, and citizens avoided public roads. Contemporary imperial sources record instances of price gouging, as “those engaged in business, crafts, and agriculture, and the shipmasters as well—have abandoned themselves to avarice and ask prices and wages two or three times those of old custom.”[24] Eventually, proper burial rites ceased entirely. Bodies were thrown out on streets or left along the waterside.

Saint Sebastian pleads with Jesus for the life of a gravedigger afflicted by plague during the Plague of Justinian. (Josse Lieferinxe/Wikimedia)

The combined effects of bad weather and manpower shortages contributed to famine. Moreover, deteriorating relations between the military and peasant population were exacerbated by the economic crisis. Loss of grain revenues alongside new subsidies by Justinian to implement price controls on food led to reduced military expenditures and irregularities in soldiers’ pay.[25] Soldiers resorted to extortion of farmers, which in turn turned the populace away from both military service and agriculture, with deleterious effects on the empire’s prosperity and security.[26] By Justinian’s reign, military service was composed entirely of volunteers who were mostly poor farmers.[27] The combined effects of plague and abuses discouraged military recruitment from its most important source. This in turn crippled Byzantine military power abroad and created open conflict between two key sectors of the empire.

Disease-stricken Iroquois society, caught in seemingly endless war, also showed signs of unraveling. Traditional orderly rituals around captives were difficult to maintain in the face of a rage spreading across Iroquoia. Some captives were killed on the spot, instead of being brought to villages for torture or adoption. Drunken Onondaga youths tried to kill prisoners brought into camp before their initiation rituals could be practiced.[28]

Sweating sickness first appeared in England in 1485. It was particularly terrifying because of its novelty and marked differences from epidemics that preceded it such as plague, malaria, and typhus. The sickness targeted primarily young, healthy men as well as the rich.[29]

By the time of the outbreak, the War of the Roses culminating in conflict between King Richard III and Henry Tudor was nearing its end. In August 1485, Henry Tudor landed in Wales and began the offensive to seize Richard’s crown. Less than a month later, sweating sickness, an unknown, contagious disease, swept through Henry’s victorious army as it traveled to London for Henry’s coronation. The plague devastated the capital, causing some 15,000 fatalities including two lord mayors.[30]

The concurrence of Henry’s arrival with the outbreak meant that Henry was blamed for its spread: “The violent change of ruler and the outbreak of disease were linked as an omen of disaster, with some likely questioning whose side had received divine favor after all,” writes one historian.[31] Henry’s coronation was postponed, and the new king initiated a propaganda campaign to dispel the damaging rumor. Outbreaks of sweating sickness marred the first half of the Tudor dynasty and contributed to assertions the Tudors were illegitimate rulers.

Finally, one would expect a country that begins to emerge from a disease to be chastened. But that is not always the case. Recovering economic and military might can cause dangerous overconfidence.

Twelve years removed from the last outbreak, Athens had only begun to recover, but their recovery led to overconfidence. When the Spartan colony Melos joined the fight in 416 BCE, Athens sent an expedition to negotiate. The Athenian attitude was so strikingly haughty that it remains today a foundational expression of unsentimental realist politics. “The strong do what they can and the weak suffer what they must,” they told the Melians before besieging the city and executing the men.[32] Athenians then rejected the prudent caution of the general Nicias, and enthusiastically backed the disastrous expedition to Sicily, which would end with the eradication of the Athenian force, marking the beginning of the end for the city.[33]

Contemporary Implications

Though the death toll from COVID-19 does not seem to be as calamitous as the historical epidemics referenced here, it may influence many actors in similarly profound ways. The economic damage will affect the ability of states to project power and support armed proxy groups. But domestic pressure and new internal rivalries that emerge from the pandemic could cause some belligerents to embark on risky military endeavors in the short term.

Though the focus now is on the human and economic toll, COVID-19’s effect on the way citizens view their political, cultural, and religious leaders may ultimately cause the most far-reaching changes in the dynamics of pre-existing conflicts. The public—or at least significant portions of it—may feel betrayed by traditional decision-makers and look to new value systems and arbiters of behavior, with unpredictable consequences for war and peace. This has been especially apparent in the 2014 Ebola epidemic in West Africa. In traditional and social media, national governments received the most blame for the spread of the disease—primarily due to a perceived lack of national border control and sluggish responses.[34] Local chiefs also received backlash from the executive and the populace in instances where chiefs did not change local practices, such as burials, to prevent the spread of Ebola.[35] These accusations portrayed the governments as incompetent, inefficient, and a danger to citizens. Violence targeted institutional and medical authorities as the Ebola outbreak created new levels of distrust among the civilian populace and exploited existing tensions between citizens and the state.

Military medical staff airlifted by eight large transport planes from the People's Liberation Army Air Force in Hubei Province, February 2, 2020. (Xinhua)

Finally, some players will emerge from lockdown and recession earlier than others, and some nations will find advantage in the new reality. The return to routine can cause overconfidence and miscalculation, raising the chances of renewed conflict.

The coronavirus represents a once-in-a-generation surprise, the implications of which will not be entirely clear for years to come. Looking back at past epidemics can help leaders consider the unanticipated ways COVID-19 may influence ongoing conflicts, and help them better prepare for an uncertain future.


Lazar Berman is a researcher at the Israel Defense Force Dado Center for Interdisciplinary Military Studies and is a fellow at the Jerusalem Institute for Strategy and Security. He is a reserve officer in the Israel Defense Force. Jennifer Tischler is a research assistant at the Jerusalem Institute for Strategy and Security, and is an Israel Government Fellow. The views expressed are those of the authors and do not necessarily reflect those of the Israel Defense Force, or the Government of Israel.


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Header Image: “The Plague at Ashdod” by Nicolas Poussin (Wikimedia)


Notes:

[1] Herbert Newell Couch, "Some Political Implications of the Athenian Plague." Transactions and Proceedings of the American Philological Association 66 (1935), p. 99-100. https://www.jstor.org/stable/i212491.

[2] Philip Mazzei, Researches on the United States, ed. and trans. Constance B. Sherman, (Charlottesville, Va., I976 [orig. publ. Paris, I788]), p. 349.

[3] Daniel Richter, “War and Culture: The Iroquois Experience.” The William and Mary Quarterly, vol. 40, no. 4, 1983, p. 530-1. www.jstor.org/stable/1921807.

[4] Ibid, p. 537.

[5] Ibid, p. 537.

[6] Ibid, p. 537.

[7] Ibid, p. 540.

[8] Hodge, Adam R. "Pestilence and Power: The Smallpox Epidemic of 1780–1782 and Intertribal Relations on the Northern Great Plains." The Historian 72, no. 3 (2010). Accessed April 28, 2020. www.jstor.org/stable/24454920

[9] Ibid.

[10] Couch, "Some Political Implications of the Athenian Plague." p. 101.

[11] David Tschanz, “Typhus Fever on the Eastern Front in World War I,” Montana State University Entomology Group, http://www.montana.edu/historybug/wwi-tef.html.

[12] Ibid.

[13] Ibid.

[14] Spencer Tucker, The Great War, 1914-1918  (London: UCL Press, 1998), p. 89.

[15] Thucydides, The History of the Peloponnesian War (II.57.1.), ed. Robert Strassler (New York: Free Press, 1996).

[16] Couch, “Some Political Implications of the Athenian Plague,” p. 99.

[17] Tschanz, “Typhus Fever on the Eastern Front in World War I.”

[18] Southern New England Algonquin tribes called their leaders “sachem.”

[19] Sherburne Cook, "The Significance of Disease in the Extinction of the New England Indians." Human Biology 45, no. 3 (1973), p. 490. www.jstor.org/stable/41459892.

[20] Charles Mann, 1491: New Revelations of the Americas Before Columbus (New York: Random House, 2005), p. 67.

[21] Roger Nichols, "The Arikara Indians and the Missouri River Trade: a Quest For Survival," Great Plains Quarterly 2, no. 2 (1982), p. 82. www.jstor.org/stable/23530550.

[22] Lester K. Little, ed., Plague and the End of Antiquity: The Pandemic of 541-750 (Cambridge: Cambridge University Press, 2007).

[23] P Allen, “The ‘Justinianic’ Plague.” Byzantion, vol. 49, 1979, p. 11. www.jstor.org/stable/44172672.

[24] John Teall, “The Barbarians in Justinian’s Armies,” Speculum, vol. 40, no. 2, 1965, p. 306. www.jstor.org/stable/2855560.

[25] A Fotiou, “Recruitment Shortages in Sixth-Century Byzantium,” Byzantion, vol. 58, no. 1, 1988, p. 66. www.jstor.org/stable/44171039.

[26] Ibid., 72.

[27] Ibid, 66.

[28] Richter, “War and Culture,” p. 543.

[29] John Wylie and Leslie Collier, “The English Sweating Sickness (Sudor Anglicus): A Reappraisal.” Journal of the History of Medicine and Allied Sciences, vol. 36, no. 4, 1981, p. 426. www.jstor.org/stable/24625462.

[30] Rebecca Seaman ed, Epidemics and War: The Impact of Disease on Major Conflicts in History (Santa Barbara: ABC-CLIO, 2018), p. 43.

[31] Ibid.

[32] Thucydides. History of the Peloponnesian War, 5.89.

[33] Couch, “Some Political Implications of the Athenian Plague,” p. 101-102.

[34] Melissa Roy et al. “Ebola and Localized Blame on Social Media: Analysis of Twitter and Facebook Conversations During the 2014-2015 Ebola Epidemic.” Culture, Medicine and Psychiatry vol. 44,1 (2020). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7088957/.

[35] Daniel Finnan, “Local chiefs refuse to be blamed for spread of Ebola in Sierra Leone, interview,” RFI, November 11, 2014. https://www.rfi.fr/en/africa/20141118-local-chiefs-refuse-be-blamed-spread-ebola-sierra-leone-interview.