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The Significance of Disease Driving Historical Change Between 1500 and 1800

Simran Singh is a student at Griffith University studying for a Bachelor of Arts degree in creative writing and art history.


Disease played a critical role in shaping the global landscape between 1500 to 1800 through its impact on warfare and the nature of slavery. Numerous diseases continually undermined the efforts of indigenous people to protect or reclaim their land as shown through the impact of smallpox and cocoliztli in their communities.

Smallpox particularly undermined the indigenous’ ability to fight through the mass death of their armies while Europeans held a higher immunity to such diseases. Ideas of biological warfare contributed to the failure of the Pontiac Rebellion due to Europeans providing Native Americans with infected items. Smallpox resulted in the deaths of key political figures in the Incan Empire during the Spanish conquest, resulting in the psychological disarray and civil war which left the Empire vulnerable to Spanish success.

Like the Incan Empire, the Aztec Empire suffered mass deaths due to multiple smallpox and cocoliztli epidemics, taking leaders and soldiers needed to withstand European invasion. The successes of the Europeans aided by disease allowed for the establishment of the New World and the slavery of the indigenous.

The crippling effect disease played on the lifespans of the indigenous led to the Transatlantic Slave Trade and the conscription of Europeans to support the colonies. Therefore, disease played a pivotal part in the establishment of the New World between 1500 to 1800 causing the rise of global European dominance.


The establishment of the New World between 1500 to 1800 was riddled with a history of the disease which greatly impacted warfare, the Old World, and European colonies. Diseases were introduced to the Old World by European people through the Colombian Exchange which was the exchange of food crops, diseases, and populations between the New and Old Worlds after Christopher Columbus voyaged to America in 1492 (Nunn; Qian, 2010 p. 163).

Smallpox was further spread by Spanish and Portuguese conquistadors (Riedel 2005, p. 21).

Diseases also introduced to the Old World included “smallpox, measles, whooping cough, chickenpox, bubonic plague, typhus, and malaria” (Denevan 1976, p. 5). Smallpox was a prominent killer which was characterised by symptoms similar to influenza and rashes while haemorrhaging beneath the skin foretold death to be an inevitability (Fenn 2000, p. 1559).

Cocoliztli was a disease with symptoms such as fever, headache, dysentery, pain in the abdomen, dark urine, neurological disorders and bleedings from the nose, eyes, and mouth (Acuna-Soto, Cleaveland, Therrell, Stahle 2002, p. 360).

Smallpox and cocoliztli epidemics led to the downfall of the Aztec Empire in 1521, due to an assault led by Hernan Cortes (Brinkerhoff 2016, p. 175). Similarly, smallpox led to the fall of the Incan Empire in 1572 via an assault led by Pedro de Alvarado (Crosby 1967, p. 337). Smallpox further debilitated the efforts of the Native Americans to reclaim land conquered by the British as seen by the impact it had over the Pontiac Rebellion from 1763 to 1766 (Bouquet, H., Kent, D. H., Stevens, S. Kirby 209).

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The European successes in consolidating and claiming land resulted in the enslavement of natives in which deaths caused by disease created a need for more slaves, resulting in the Transatlantic Slave Trade in the 16th century (Nunn; Qian, 2010 p. 164).

The Columbian Exchange

Small Pox And Native Americans

Disease contributed to the consolidation of European powers over America, shaping the landscape of which European Empires gained and maintained power over the New World. Smallpox primarily affected indigenous people which led to mass deaths that physically impacted their warfare capabilities. An instance in which this occurred was in Fort Pitt, 1763, during the Pontiac Rebellion.

Initially, the rebellion challenged British rule within this area and saw success through the capture of most British forts (Bouquet; Kent; Stevens 1940-1943, p. 209). Overall success in this rebellion would have contributed to Native Indians reclaiming their land, however, the disease was weaponised as history’s first instance of biological warfare. Colonial Henry Bouquet wrote a letter to Sir Jeffery Amherst on 13th July 1763 stating, “I will try to inoculate the (Indians) with some blankets that may fall in their hands, and take care not to get the disease myself” (Bouquet; Kent; Stevens 1940-1943, p. 214). After writing this the “smallpox blanket” incidence occurred where the Indians parleyed with the British, asking for a “little Provisions and Liquor, to carry us Home."

William Trent wrote they gave them blankets and a handkerchief from the smallpox hospital in hopes it would have “the desired effect” of infecting the natives (Fenn 2000, p. 1553). Later Hicks reported the epidemic raged amongst the Delawares and Shawneese, causing mass death which crippled the rebellion and triggered its failure (Fenn 2000, p. 1557). This delineated the impact of disease as a driving force of change as it gave the British the advantage in warfare against natives considering their higher immunity to diseases such as smallpox. Disease contributed to European victories which allowed them to expand their colonies, maintain a dominant presence in America, acquire slaves and economically benefited their empires through the trade of resources and plantations.

Hence, the prominent impact of disease in warfare ensured the dominance Europeans held over areas such as America, playing a decisive factor on which empires posed as superpowers in the New World.

Disease In The Downfall Of The Incan And Aztec Empires

The impact of disease on indigenous tribes paved the way for European control over the New World. For example, smallpox had a devastating impact on the Incan Empire which assured Spanish victory at the Battle of Cajamarca in November 1532 (Brinkerhoff 2016, p. 174).

Smallpox triggered civil wars in the Incan Empire through taking political figures, which led to disarray, high levels of psychological distress and demoralisation which paved the way for Spanish conquest. The ruler Huayna Capac perished from the disease which impacted Incan society in a way Cieza de Leon described “shrieks rose to the skies… nowhere did it not evoke great sorrow,” which delineated the emotional impact of the loss (Crosby 1967, p. 335).

Further impacts were seen through the deaths of military leaders such as Mihenaca Mayta, the governors Apu Hilaquito and Auqui Tupac, members of the royal family and the Inca’s son and heir Ninan Cuyoche (Crosby 1967, p. 335). The deaths of political and military figures rendered the empire unstable with difficulties in defending itself through the impacted morale and military prowess.

Morale was already fragile due to the Spaniards’ immunity to smallpox, causing Incans to believe they were superhuman and protected by the gods (Crosby 1967, p. 337). The shock was further supplemented Aztec and Incan prophesies about white gods (Crosby 1967, p. 337). It was clear the way disease held a greater impact on indigenous communities rather than Europeans caused speculations that sabotaged the Incan’s morale in battle.

Furthermore, the deaths caused by smallpox sparked a civil war between Huascar and Atahualpa who fought over who was to become the next Child of the Sun (ruler of the empire) (Crosby 1967, p. 336). The death and disarray caused by the war left the empire vulnerable to conquest.

According to Pedro Pizarro, the divided land ensured victory as if it was not for the war, more manpower was required for conquest which was impossible to acquire (Crosby 1967, p. 336).

Resultantly, the political impact of smallpox significantly impacted the stability and defences of the Incan Empire, which demonstrated how disease ensured European control of the New World.

The Fall Of Mexica

The significant effect of disease on indigenous empires allowed for European conquest and control over the New World. Diseases ensured European victory in empires such as Mexica as it caused mass death, political upheaval, magnified the effects of drought and famine and ultimately allowed Europe to enslave the population.

Numerous epidemics inflicted Mexica at the beginning of the European conquest such as the smallpox epidemics of 1519 to 1520 and 1545 to 1576 where approximately 25 million people perished (Acuna-Soto, Cleaveland, Therrell, Stahle 2002, p. 360).

This was followed by the epidemics of cocoliztli between 1545 to 1548 which was the most disastrous epidemics in human history which killed up to 80% of the population (Acuna-Soto, Cleaveland, Therrell, Stahle 2002, p. 360). An additional 2 to 2.5 million people died due to the cocoliztli epidemic from 1576 to 1578. This caused the collapse of the population while disease accentuated the impacts of famine due to the Spanish cutting off available food (Brinkerhoff 2016, p. 177). Epidemics often followed famine caused by major crop failures as starvation often corresponded with disease.

The disease also impacted Mexico politically and militarily according to Sahagun’s accounts of the conquest completed in 1585, stating Mexica’s lord Cuitlahuactzin, leaders, veteran soldiers and many fighters died to pestilence (McCaa 1995, p. 408). This significantly decreased Mexica’s defences, destroying the endurance of Mexica to withstand the Spanish invasion (Crosby 1967, p. 330). This triggered the downfall of Mesoamerica as the fall of Tenochtitlan caused the rest to fall to Spanish rule (Crosby 1967, p. 411).

As highlighted, disease played an important factor in the success of European conquest through crippling indigenous empires, which resulted in enslavement, abusive labour demands, ecological devastation, and tribute payments (Crosby 1967, p. 429). Therefore, the impact of disease allowed for European domination over the New World through crippling enemy empires politically and militarily.


Slavery And Disease

After the consolidation of European victories, disease shaped the way in which slavery supported such colonies. Death caused by disease created a demand for more slaves which escalated into a large slave trade system used to fuel European colonies.

Native Americans had no immunity to diseases introduced by the Europeans such as measles, smallpox, and typhus (Denevan 1976, pp. 1-12). This resulted in slaves taken to replace dying workers dying early while causing a shortage of native Americans to enslave (Crosby 1967, p. 128). With the failing crops in the Americas and the deaths of native populations, slave labour went into demand which caused the enslavement and relocation of 12 million Africans during the sixteenth to nineteenth centuries (Nunn; Qian, 2010 p. 164).

Through the loss of battles sought to defend the land, disease handicapped the ability of native Americans to defend themselves, rebel against the Europeans and lead to the Transatlantic Slave Trade.

However, the deaths caused by disease further shaped the face of slavery as white convicts became conscripted while some were kidnapped in order to fill this void (Crosby 1967, p. 125). Resultantly, disease created a chain effect that led to the abuse of native Americans as they became the backbone of economic prosperity for colonisers.

Disease! Crash Course World History 203


From the impact disease had on the success of European powers as noted through suppressing rebellions, conquering the Aztec and Incan Empires, and ensuring slaves would support their colonies, it was clear disease had a considerable impact as a driver of change.

Europeans introduced diseases such as smallpox and cocoliztli into the Old World which substantially aided them in conquering land. The deaths caused by the English giving the Native Americans infected blankets and a handkerchief caused an epidemic that crippled the success of the Pontiac Rebellion.

The debilitating impact smallpox played on the political stability of the Incan Empire ensured European victory by sabotaging the Empire’s defences and military. Millions of Aztec people passed away due to smallpox and cocoliztli, indicating the deadly nature of disease through its political and military impacts which allowed for European conquest.

The European conquests caused the expansions of colonies, a dominant standing within America, enslavement of the indigenous with abusive conditions and the creation of plantations.

The colonies supplied the Empire with economic success built on the backbones of slaves during the Transatlantic Slave Trade and European convicts. Ultimately, history epidemics will be an important driver of change which impacts how societies operated politically, socially, and economically.

Reference List

Bouquet, H; Kent, D. H; Stevens, S Kirby 1940-1943, The papers of Col. Henry Bouquet, Harrisburg, Pennsylvania Historical Commission.

Brinkerhoff, Thomas J. 2016, ‘Reexamining the Lore of the "Archetypal Conquistador": Hernán Cortés and the Spanish Conquest of the Aztec Empire, 1519-1521,’ The History Teacher, vol. 49, no. 2, pp. 169-187. Retrieved 7 February 2022, from JSTOR Database.

Crosby, Alfred W. 1967, ‘Conquistador y Pestilencia: The First New World Pandemic and the Fall of the Great Indian Empires,’ The Hispanic American Historical Review, vol. 47, no. 3, pp. 321-337. Retrieved 7 February 2022, from JSTOR Database.

Denevan, William M 1976, ‘Introduction to The Native Population of the Americas in 1492,’ Journal of Economic Perspectives, vol. 18, pp. 61–12. Retrieved 7 February 2022, from JSTOR Database.

Fenn, Elizabeth A. 2000, ‘Biological Warfare in Eighteenth-Century North America: Beyond Jeffery Amherst,’ The Journal of American History, vol. 86, no. 4, pp. 1552-1580. Retrieved 7 February 2022, from JSTOR Database.

McCaa, Robert 1995, ‘Spanish and Nahuatl Views on Smallpox and Demographic Catastrophe in Mexico,’ The Journal of Interdisciplinary History, vol 25, no. 3, pp. 397-431. Retrieved 7 February 2022, from JSTOR Database.

Nunn, Nathan; Qian, Nancy 2010, ‘The Columbian Exchange: A History of Disease, Food, and Ideas,’ Journal of Economic Perspectives, vol. 24, no. 1, pp. 63–188. Retrieved 7 February 2022, from JSTOR Database.

Riedel, Stefan 2005, ‘Edward Jenner and the history of smallpox and vaccination,’ BUMC PROCEEDINGS, vol. 18, no. 1, pp. 21–25. Retrieved 7 February 2022, from JSTOR Database.

Acuna-Soto, Rodolfo; Cleaveland, Malcolm K; Therrell, Matthew D; Stahle, David W 2002, ‘Megadrought and Megadeath in 16th Century Mexico,’ Historical Review, vol. 8, no. 4, pp. 360-362. Retrieved 7 February 2022, from JSTOR Database.

This content reflects the personal opinions of the author. It is accurate and true to the best of the author’s knowledge and should not be substituted for impartial fact or advice in legal, political, or personal matters.

© 2022 Simran Singh

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