1. Infectious disease (by far the largest) -- Our World in Data
2. Death in infancy, childhood, and childbirth -- Brilliant
3. Famine and severe malnutrition -- sites.tufts
4. Violence: war, massacre, and homicide
Large in absolute terms, smaller than endemic disease. World War II is about 70–85 million deaths, including famine and disease linked to the war. R. J. Rummel’s compilation of pre-20th-century democide (genocide, massacre, executions, and similar killing) has a midpoint around 133 million, with a very wide range, and he treats that as an undercount. Even stacked together, recorded mass violence does not approach the toll of routine infection.
World War I: about 15–20 million deaths, including civilians. Famine and disease were a large share.
World War II: about 70–85 million, including the Holocaust, war famines in the Soviet Union, China, Bengal, and Vietnam, and strategic bombing.
Crusades, about 1095–1291: often cited around 1–3 million; some compilations stretch to 1–9 million over two centuries. A large share was disease and starvation on campaign.
Thirty Years’ War, 1618–1648: about 4.5–8 million in central Europe. It was a religious and political war; most deaths were famine and disease, not battle.
Inquisitions: executions were in the thousands to low tens of thousands over centuries. Claims of tens of millions killed by the papacy come from 19th-century religious polemics and are not accepted by historians.
Conquest of the Americas: indigenous populations fell by tens of millions. The dominant cause was Old World disease, especially smallpox, not mass execution. Direct killing and forced labor still killed large numbers, but they are not the same as the population collapse.
Taiping Rebellion, 1850–1864: about 20–30 million. It was led by a heterodox Christian movement in China and is the largest single death toll with a Christian label. It was a civil war, not a church campaign.
Early Arab conquests: poorly counted; the credible range is hundreds of thousands to low millions, not tens of millions.
Timur (Tamerlane), a Muslim Turco-Mongol conqueror, late 1300s: commonly estimated around 15–20 million across Persia, Iraq, India, and Central Asia, including the Delhi massacre of captives. This is the largest single well-cited total on this side.
Medieval India: court chronicles record repeated massacres. K. S. Lal’s figure of 60–80 million dead between 1000 and 1525 is widely repeated online and rejected by many academic historians.
