The Siege in Medieval Times: Besieging a Castle in the Middle Ages

A Castle was Built to Withstand a Siege

Medieval warfare – the tactics, methods and weaponry used to lay siege to a castle in medieval times.

The siege was a popular technique of medieval warfare and aimed to force the enemy to abandon a castle (or sometimes a whole town) or die in its defence. The aim was to gain entry to the castle, but not destroy it, as the building would be ultimately taken and used by the successful attackers.

Besieging a Medieval Castle

A castle was built to withstand a siege and so any attacking force began at a disadvantage. The site of a castle was chosen with care and was usually on high ground, so that attacking armies could be seen long before they approached the building.

Some castles had a river or the sea on one side, making an approach difficult. Others, such as Edinburgh castle in Scotland, were built on a large rocky outcrop, forcing attackers to climb steep walls.

Preparing for a Medieval Siege

Siege weaponry was usually created at the scene of a siege. The battle commander would assess the scene and determine what weapons were needed to attack at that particular site. Most siege weapons were large and cumbersome and couldn’t have been transported over long distances.

The attacking force had to choose a site where they could eat and sleep in relative safety, out of range of weapons thrown from the inhabitants of the castle. They also had to ensure they could defend themselves if an army should come to the defense of the castle from another direction.

Siege Weapons in the Middle Ages

Among the most popular types of siege weapons were those which threw missiles over a long distance. The trebuchet was an advanced catapult. It was positioned outside the castle walls and a heavy weight was dropped onto one end, making the shorter end spring up with force, releasing the chosen projectile.

A ballista was a combination of wooden arms and ropes. It used force to shoot multiple arrows faster than a single marksman could.

A siege tower was a large wooden structure, at least as tall as the castle walls and was often mounted on wheels, so it could be moved to where it was needed. Although it had the advantage of placing the archers within easy range of the defending army, it was vulnerable to fire or being toppled by its attackers.

Gunpowder and Tunnelling in a Castle Siege

Most successful sieges had to rely on a number of methods, which in combination caused the castle to fall to into the hands of its attackers. The use of gunpowder and tunnelling allowed parts of the castle to be destroyed while the main force concentrated on using siege weapons for the attack.

A petard was an early type of bomb, which could be powerful enough to destroy a castle gate or entrance. Its big disadvantage was that it had to be physically fixed to the structure it was intended to destroy. This put the attackers at enormous risk from being hit by arrows or drenched in boiling oil thrown from the highest walls of the castle.

The petard was packed with gunpowder and lit by a slow fuse. If the castle entrance was breached, or even partially damaged, the attackers could then use a battering ram to gain entry and attack from inside.

Some armies had tunnellers who would dig from their camp towards the castle walls. When they reached the castle foundations, they would replace some of the foundation stones with pieces of wood. They would retreat, start a fire in the tunnel and see if the fall of the burning wood caused the collapse of the walls.

Starving out the Inhabitants of a Medieval Castle

In order to force the inhabitants of a castle to leave, their attackers had to ensure that food and water couldn’t reach them. Sometimes the water supply would be poisoned and some armies resorted to throwing the corpse of an animal or even a human, into the castle, to try and spread disease.

A castle could hold out for months, even years, if well prepared for a siege. The inhabitants would hope that the attackers would lose interest or face attack themselves and retreat, leaving the castle to a period of peace.

As the medieval period drew to a close, a castle became more of a home than a defence system and life was more about tournaments and displays, rather than pitched battles.


  1. Bradbury, Jim, The Medieval Siege [Boydell Press,1998]
  2. Norris, John, Medieval Siege Warfare [Tempus,2006]