Medieval warfare: tactics, siege engines and castles

By The GroLearning Team, 17 June, 2026

WHAT YOU'LL LEARN

Medieval warfare: tactics, siege engines and castles

Warfare in the reign of Edward I combined the great set-piece cavalry battle with the grinding reality of siege — and Edward excelled at both. His Welsh campaigns showed how to use logistical superiority and naval control to force a difficult enemy to submit without fighting. His Scottish campaigns showed the power of combined arms (cavalry, longbowmen, spearmen) and the importance of tactical coordination. His castle-building programme produced the most sophisticated military architecture of its age. This page covers how medieval warfare actually worked, from the battlefield to the siege to the castle garrison.

The medieval army: who fought and how

A medieval army in Edward I's time was a composite force:

Heavy cavalry (knights): The social elite of medieval warfare. A fully equipped knight — horse, armour (mail hauberk or, increasingly, plate), lance, sword, shield — was enormously expensive. Knights fought as shock cavalry: the charge of armoured horsemen was devastating if it connected, but could be broken by disciplined infantry in good defensive ground.

Infantry: Foot soldiers formed the bulk of most medieval armies. They carried spears, billhooks, halberds, and swords. Edward's Welsh campaigns gave him access to large numbers of Welsh infantry — particularly archers from south Wales — who became the core of his infantry force.

The Welsh/English longbow: The longbow was the signature weapon of Edward I's armies. It was not a new weapon, but Edward's campaigns systematised its use. A skilled longbowman could loose 10–12 arrows per minute at ranges up to 250 metres. At Falkirk (1298), Edward's archers broke the Scottish schiltrons that had resisted his cavalry — showing that the longbow had made disciplined infantry vulnerable in a new way. The longbow would dominate English warfare for another 150 years.

Key tactic

The schiltron

The Scottish **schiltron** was a formation of infantry armed with long spears (12–18 feet), standing closely together to form a hedgehog-like mass. In good defensive ground, it was almost impossible for cavalry to charge: the horses refused to impale themselves on the spears. At Stirling Bridge (1297), Wallace's schiltrons destroyed the English cavalry that crossed into his killing zone. But schiltrons had weaknesses: they were nearly immobile (they could not easily advance or change direction) and were vulnerable to archers. At Falkirk (1298), Edward simply directed his archers against the stationary Scottish formations and broke them before his cavalry charged. The schiltron illustrates how medieval warfare was about finding the right response to each weapon or tactic.

Siege warfare

For most of the medieval period, siege was more important than battle. Most warfare consisted of taking or defending fortifications — castles, walled towns, and fortified monasteries. Pitched battles were risky and avoided when possible; sieges were methodical and predictable.

Methods of attack:

  • Blockade: Simply surround the castle and starve the garrison into submission. Slow but reliable if the besieger could maintain a sufficient force and supply system.
  • Mining: Dig tunnels under the walls, fill them with combustible materials, burn the supports, and the wall above collapses. Counter: defenders dug their own tunnels to detect and disrupt mining operations.
  • Escalade: Direct assault with ladders. Dangerous and casualties were high, but sometimes necessary.
  • Siege engines:

- Trebuchet: The dominant siege engine of the thirteenth century. A counterweight trebuchet used a falling counterweight to propel a projectile (heavy stone, or diseased animal carcasses to spread disease) over castle walls. Range up to 300 metres; projectiles could weigh 50–150 kg. - Mangonels and ballistas: Other throwing engines using torsion or tension mechanisms. - Belfry (siege tower): A tall wooden tower moved against the castle wall to allow attackers to fight on the battlements.

Edward used siege machines extensively. At the siege of Stirling Castle in 1304, he deployed "Warwolf" — reportedly the largest trebuchet ever built in England, so large it took three months to construct.

Engineering achievement

Concentric castle design

The major development in castle design in the thirteenth century was the **concentric castle**: multiple rings of defensive walls, one inside the other, so that attackers who breached the outer wall were then faced with the inner wall — and could be attacked from the walls on both sides. Master James of St George's Edwardian castles in Wales were the finest examples of concentric design in Britain. Key features: the outer wall was high enough to prevent siege towers reaching the inner wall; twin-towered gatehouses were more defensible than a single gate; wall towers provided overlapping fields of fire. The design meant a small garrison could hold a large castle against a much bigger force — essential for Edward's strategy of controlling Wales with a limited number of troops.

Edward's military strategy in Wales

Edward's Welsh campaigns were not primarily about pitched battles — they were about logistics and starvation. His strategy in 1277 was to:

  • Advance along the north Welsh coast with a large army, building roads as he went
  • Use his fleet to supply the army and control the sea lanes
  • Cut off Anglesey, the main source of food for Gwynedd, by using the fleet to blockade and then occupy the island
  • Wait for Llywelyn to submit — which he did, without a major battle

This strategy shows Edward's understanding that winning did not require fighting; it required controlling the conditions under which the enemy could operate.

Why this matters for the exam

Warfare and power in the reign of Edward I

AQA questions on medieval warfare often connect to the wider question of how Edward exercised power. Key points: Edward combined military and logistical skill (the Welsh campaigns showed strategy as much as battle); his use of the longbow was an early example of infantry changing the balance against cavalry; his concentric castles were instruments of political control as much as military defence; and siege warfare was the dominant form of conflict, not pitched battles. A strong answer shows that medieval warfare was about more than fighting — it was about feeding armies, controlling terrain, cutting off supplies, and projecting power through permanent structures like castles.

Revision checklist

Before moving on, make sure you can answer:

  1. Describe the main types of soldiers in Edward I's army.
  2. What was the longbow? Why was it significant?
  3. What was a schiltron? What were its strengths and weaknesses?
  4. What was a trebuchet? How was it used in siege warfare?
  5. What other siege methods were used in medieval warfare?
  6. What was a concentric castle? What made it more defensible than earlier castle designs?
  7. What was Edward's military strategy in Wales in 1277? Why was it effective?
  8. Why was siege warfare more common than pitched battle in the medieval period?

What's New snippet

Article slug: gcse-history-medieval-england-warfare-siege-castles

Title: Trebuchets, schiltrons, and concentric walls — how medieval warfare actually worked

Medieval warfare was not primarily about cavalry charges and individual heroism — it was about siege, supply, and controlling the conditions under which the enemy could operate. Edward I's famous Warwolf trebuchet at Stirling in 1304 took three months to build. His Welsh campaign of 1277 was won not by battle but by cutting off Anglesey's food supply. This page explains how medieval armies fought, besieged, and built.