The big idea: Treaties redraw borders on paper, but war redraws populations on the ground. Behind every campaign map is a human story of who died, who fled, who was forced to move, and who never came back.
This micro gives you a sixth 'drawer' to add to your effects framework: demographic change — the impact of war on the size, location and make-up of a population.
Examiners often ask you to "examine the effects of war on the population" or to weigh the human cost inside a wider essay. Too many students mention casualties in one sentence and stop there.
A strong answer breaks demographic change into distinct strands: deaths, famine and disease, displacement, depopulation and resettlement, and forced migration. Each is a separate, examinable point.
This pattern repeats across very different medieval wars. The Crusades, the Hundred Years' War, and the Mongol conquests all produced casualties, famine, refugees and resettlement — even though the wars themselves looked nothing alike.
- War casualties — soldiers and civilians killed in battle, sieges and raids
- Famine and disease — hunger and illness that follow armies and ruined harvests
- Displacement and refugees — people driven from their homes by fighting
- Depopulation and resettlement — emptied regions later refilled by new settlers
- Enslavement and forced migration — captives marched or shipped far from home
- Long-term population shifts — permanent changes to where and how many people live
Why this drawer earns marks: Demographic change is easy to describe but hard to analyse well. Always link the human cost back to a bigger consequence — did it weaken an economy, break a siege, empower survivors, or change who lived on conquered land?
A casualty figure alone is a fact. Explaining what that death toll caused is analysis.
Free preview
This is the free notes preview
You're reading the free notes. Aimnova Pro unlocks the full study experience — and you can try it free for 7 days:
- FlashcardsLock in vocabulary and key terms with spaced repetition.
- Practice questionsAnswer exam-style questions and get instant AI marking.
- Mock exams & past-paper vaultSit full mocks and see exactly how examiners award marks.
- Personalised study planA daily plan built around your exam date and weak areas.
The first wave: killing and starving
The most direct demographic effect of war is death — in battle, in sieges, and in the raids armies used to terrorise enemy land. But medieval warfare killed in a second way too: by destroying the food supply that kept people alive.
1 · Battle and siege deaths
Pitched battles could kill thousands in a single day, but sieges were often deadlier. When the Crusaders stormed Jerusalem in July 1099, they massacred much of the city's Muslim and Jewish population — chroniclers on both sides described the slaughter as immense.
2 · Deliberate devastation
In the Hundred Years' War, English armies rode the chevauchée across French land. The goal was not to fight a battle but to destroy the enemy's ability to feed and fund itself — a strategy that killed through starvation as much as through the sword.
3 · Famine and disease
Burned crops and slaughtered livestock meant famine followed close behind the soldiers. Refugee camps and besieged towns, crowded and poorly fed, became breeding grounds for disease, so plagues often spread fastest in the years a war was fought.
Killing was only the first way medieval war reduced a population — starving people was just as deadly.
The Mongols and mass slaughter: The Mongol conquests caused demographic destruction on an extreme scale. Cities that resisted, such as Baghdad in 1258, could see their entire population massacred as a deterrent to other cities.
Historians estimate Mongol campaigns killed millions across Central Asia, Persia and China — a demographic catastrophe that reshaped entire regions for generations.
Direct human cost
- Deaths in battle and sieges
- Massacres of civilians (Jerusalem, 1099; Baghdad, 1258)
- Executions and reprisals against resisting towns
Indirect human cost
- Famine from burned crops and slaughtered animals
- Disease spreading through crowded, weakened populations
- Long-term drops in birth rates after huge losses of young men
Direct vs indirect deaths: Top answers separate direct deaths (killed by weapons) from indirect deaths (famine, disease). Chroniclers usually only recorded the dramatic direct deaths, so historians must reason carefully about the much larger indirect toll — a good point to make when evaluating sources or estimates.
See how examiners mark answers
Access past paper questions with model answers. Learn exactly what earns marks and what doesn't.
War does not just kill — it moves people. Families fled fighting, whole regions were emptied of their original population, and prisoners were marched off to serve new masters far from home.
These movements often mattered as much to the outcome of a war as any single battle.
Displacement and refugees
As armies approached, villagers abandoned their homes rather than risk death or capture. In the Hundred Years' War, French peasants regularly fled the path of an approaching chevauchée, crowding into walled towns or the countryside further away, which itself strained food supplies and spread disease among the displaced.
Depopulation and resettlement
Years of raiding could leave a region almost empty of its original population. Conquerors then resettled it with their own people to secure control — the Mongols, for instance, moved skilled craftsmen and administrators from conquered cities to serve the empire elsewhere, permanently changing who lived where.
Enslavement and forced migration
Captives from a defeated side were frequently enslaved or forcibly relocated rather than killed. Mongol campaigns are especially well documented for this: skilled artisans, scholars and administrators were marched thousands of kilometres to serve the growing empire, scattering populations across Eurasia.
The Crusades and displaced communities: The First Crusade (1096–1099) triggered its own wave of displacement even before reaching the Holy Land: Crusader bands attacked Jewish communities in the Rhineland in 1096, killing many and forcing survivors to flee.
In the Levant, the fall of cities such as Jerusalem in 1099 and Acre in 1291 each triggered fresh waves of refugees moving in and out of the region as rulers changed.
| Pattern | Crusades | Hundred Years' War | Mongol conquests |
|---|---|---|---|
| Casualties | Massacre at Jerusalem, 1099 | Deaths from chevauchée raids | Mass killing of resisting cities, e.g. Baghdad, 1258 |
| Famine/disease | Long marches and sieges caused starvation | Burned harvests caused famine in France | Cities under siege starved before surrender |
| Displacement | Rhineland Jewish communities flee, 1096 | French peasants flee raided regions | Populations flee advancing armies across Asia |
| Resettlement/migration | New settlers in Crusader States after 1099 | Depopulated French villages resettled slowly after 1453 | Skilled captives resettled across the Mongol Empire |
Long-term population shifts: The biggest demographic effects were often permanent. Regions devastated by decades of war took generations to refill, populations scattered by forced migration never returned home, and the balance of who lived where in Europe and Asia was changed for centuries — not just for the length of the war itself.