Causes of the Hundred Years' War
The Hundred Years' War was a series of conflicts between England and France lasting from 1337 to 1453. Dynastic disputes, economic rivalries, and territorial tensions all fed into the conflict, which reshaped medieval warfare, politics, and society across Western Europe.
Dynastic Disputes and the Salic Law
When Charles IV of France died in 1328 without a direct male heir, a succession crisis erupted. Edward III of England claimed the French throne through his mother, Isabella of France, who was Charles IV's sister.
The French nobility rejected this claim by invoking Salic law, which excluded inheritance through the female line. Instead, they crowned Philip VI of the House of Valois. Both monarchs insisted they were the rightful king of France, and this unresolved dispute became the central justification for war.
Economic and Territorial Conflicts
Trade rivalries sharpened the tension between the two kingdoms:
- Flanders and the wool trade: Flanders produced Europe's finest textiles but depended on English wool as its raw material. The French crown tried to assert control over Flanders, which threatened English economic interests and pushed the Flemish toward an English alliance.
- Gascony: England held the duchy of Gascony in southwestern France, a valuable wine-producing region. French kings repeatedly tried to extend their authority over Gascony, while English monarchs refused to give up their continental holdings. This feudal tug-of-war was a constant source of friction.
Political Alliances and Complexities
The conflict drew in outside powers. Holy Roman Emperor Louis IV backed Edward III's claim to the French throne, creating a broader threat to France. Meanwhile, Flanders' economic ties to England and its resistance to French control made it a natural English ally. French attempts to bring Flanders to heel only pushed the region deeper into the Anglo-French rivalry, widening the conflict beyond just two kingdoms.
Key Battles and Turning Points
Early English Victories
Battle of Sluys (1340): The English fleet destroyed a larger French fleet in the English Channel, establishing naval supremacy. This victory protected English trade routes and made it far easier to transport armies to France.
Battle of Crécy (1346): Edward III's outnumbered army defeated a much larger French force, largely thanks to the English longbow. Massed volleys of arrows devastated the French cavalry before they could close to melee range. Crécy demonstrated that well-positioned infantry with ranged weapons could overcome mounted knights.
Capture of Calais (1347): After Crécy, the English besieged and captured the port city of Calais. It became England's most important foothold in northern France, serving as a supply base and staging point for future campaigns. England would hold Calais for over two centuries.
French Setbacks and Political Instability
Battle of Poitiers (1356): The Black Prince (Edward, Prince of Wales) led English forces to another decisive victory. The French king, John II, was captured on the battlefield. With the king a prisoner in England, the Dauphin (the future Charles V) struggled to govern a kingdom in crisis. Peasant revolts and political infighting plagued France during this period.
Treaty of Brétigny (1360): This treaty temporarily ended the fighting. England gained major territorial concessions, including full sovereignty over Gascony and Calais. In return, Edward III renounced his claim to the French throne. The treaty marked the lowest point for France in the war, though its terms would not hold for long.
English Resurgence under Henry V
Battle of Agincourt (1415): Henry V of England revived English ambitions in France. At Agincourt, his exhausted, outnumbered army defeated a far larger French force. Once again, the longbow proved devastating against armored cavalry advancing across muddy terrain. The victory made Henry V a legendary figure.
Treaty of Troyes (1420): Following his military successes, Henry V negotiated this treaty with the French crown. It disinherited the French Dauphin (the future Charles VII) and recognized Henry V as heir to the French throne. This was the high-water mark for England in the war. However, Henry V died unexpectedly in 1422, and the French resistance that followed, galvanized by Joan of Arc, would reverse these gains.
Notable Figures in the War
English Leaders and Military Commanders
- Edward III initiated the war by pressing his claim to the French throne. He led the victories at Sluys and Crécy and set the strategic direction for England's early dominance.
- The Black Prince (Edward of Woodstock), son of Edward III, was one of the war's most celebrated commanders. His victories at Crécy and Poitiers, where he personally captured the French king, cemented his reputation as a chivalric hero. His early death in 1376 deprived England of its best military leader.
- Henry V revived English fortunes a generation later. His victory at Agincourt and the Treaty of Troyes brought England closer to controlling France than at any other point in the war.
French Resistance and Leadership
- Charles V ("the Wise") stabilized France during his reign (1364–1380) after the disasters of Crécy and Poitiers. Rather than meeting the English in pitched battles, he reformed the French army and relied on guerrilla tactics, avoiding large engagements while gradually recovering lost territory. His strategic patience proved highly effective.
- Joan of Arc, a peasant girl from Domrémy, became the most iconic figure of the war's final phase. In 1429, she led French forces to lift the Siege of Orléans and escorted Charles VII to his coronation at Reims, a powerful symbolic act that legitimized his kingship. Though captured and executed by the English in 1431, her leadership revived French morale at a critical moment and helped turn the war decisively in France's favor.
Intermittent Warfare and Prolonged Duration
Phases of Conflict and Periods of Truce
The Hundred Years' War was not one continuous fight. It unfolded in distinct phases separated by truces and periods of relative peace, such as those following the Treaty of Brétigny (1360) and the Treaty of Troyes (1420). These pauses provided temporary relief but never resolved the underlying dynastic and territorial disputes.
The recurring nature of the succession claim kept reigniting the conflict. As new monarchs came to power on both sides, they often renewed their predecessors' claims to the French throne, restarting the cycle of war.
External Factors and Constraints
- The Black Death (1348–1350) killed roughly a third of Europe's population and disrupted military campaigns on both sides. The massive loss of life and economic upheaval made it impossible to sustain large-scale warfare for years afterward. Subsequent plague outbreaks continued to interrupt the fighting.
- Financial strain limited both kingdoms. Raising and maintaining armies was enormously expensive, and neither side could afford sustained campaigns indefinitely.
- Domestic unrest diverted resources from the war. The Jacquerie (1358), a violent peasant uprising in France, and the Peasants' Revolt in England (1381) forced both governments to deal with internal crises before they could refocus on the conflict abroad.
Evolution of Military Tactics and Technology
The war drove significant changes in how armies fought, and those changes in turn prolonged the conflict. The English longbow, which dominated the early and middle phases, forced the French to rethink cavalry-centered tactics. Over time, infantry became increasingly important on both sides.
The gradual introduction of gunpowder weapons, particularly artillery, began to shift the balance again. Cannons proved effective at breaking down castle walls, undermining the defensive advantage that had allowed the English to hold fortified positions across France. As each side adapted to new technologies and developed countermeasures, the military balance kept shifting, preventing either kingdom from achieving a quick, decisive victory.