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What makes a strong castle?

Published: 10 May 2016
Posted by: English Heritage
Category: History In-depth

Like many of England’s iconic Norman castles and fortresses, Prudhoe Castle in Northumberland has stood the test of time. It’s also the only Northumberland fortress that has never fallen to the Scots – despite being besieged twice. This year also marks 30 years since English Heritage opened the castle to the public.

The king and his castles

William the Conqueror brought castles to Britain after he invaded England in 1066. As the newly crowned King of England, castle building was one of the most powerful ways for him to control large areas of land, to defend his kingdom against attacking enemies, and to show off his wealth and importance.

Prudhoe Castle in Northumberland is a good example of a castle which was successful at doing all of these things. But it took some careful planning to get it right. Read on to find out what you need to build a strong castle, and what makes Prudhoe Castle special.

1. Get planning permission from the king

It took a long time and a great deal of money to build a castle – and you needed permission from the king before you could start to build one.

The design of castles also changed over time. Many were extended and modified as new building techniques and architectural styles developed. Check out the key features to look out for in a Norman castle here (and watch Dover Castle being built in Minecraft too!).

Prudhoe Castle was originally the home of the Umfraville family, and the castle that you can see today has been continuously lived in for nine centuries. We know from archaeological excavations that very earliest version of Prudhoe Castle was built between 1100 and 1120.

2. Build your castle in the right place

Castles are usually built on high ground with clear views of the surrounding lands – and both of these things make them difficult to attack. Prudhoe was built on a hill top ridge with an 18m drop on the north side and a deep ravine on the south side.

To start with, it was a wooden structure on the site of an older earthwork fortress, defending a strategic place to cross the River Tyne. Not long after it was first built, the timber parts of the defences were re-built in stone and the great tower and the lower section of the gatehouse were added.


The steep drop to the River Tyne is hidden by trees which have grown since the castle was used for defense.

It is also positioned on the south side of a river, approximately 70 miles from the Scottish border. This meant that there was time to spot any army marching south – and for news of it to reach the castle in plenty of time to prepare for an attack. 

3. Dig a moat

The south-west side of Prudhoe Castle was also protected by a deep moat. A moat is a deep, broad ditch, which can either dry or filled with water. They can surround a castle, fortification, building or town, providing it with a first line of defence – if attackers got close enough.


The moat at Prudhoe Castle

In some places moats evolved into more complex water defences, including natural or artificial lakes, dams and sluices. They also stopped people being able to tunnel underground to reach the castle from below.

Being protected from the north by a river and earthwork ridge, and then from the south by the moat, undoubtedly put Prudhoe in a very strong strategic position with very few areas of weakness for invaders to try and take advantage of.

4. Build thick walls and battlements

The approach to the castle’s main gate (the only way in) was protected by a ‘barbican’. This is a kind of fortified corridor at Prudhoe, made up of two walls on either side of the track leading to the gatehouse.


Imagine fighting your way through the barbican with missiles being thrown down form the battlements…

As attackers fought their way around towards the gatehouse, those defending Prudhoe would man the tops of these walls and fire arrows and missiles down at them.

The castle also has high ‘curtain walls’ which protect the castle’s inner and outer ‘wards’ or ‘baileys’. These are the courtyard areas inside the walls where important buildings like the keep, or perhaps stables and storehouses would have been built.

Prudhoe’s walls were 2.5 metres thick in places. They were topped by a battlement behind which was a flat stone walkway. The castle’s soldiers could use the gaps in the battlements – known as crenellations – to shoot at attackers.

5. Construct a defensive keep

The great tower or ‘keep’ is typically where the lord of the castle would take refuge if needs be.  But in Prudhoe’s case, the attacking army never infiltrated the walls.

In 1174, after four nights King William’s army were forced to retreat by the knights Odinel Umfraville called to his assistance, and ‘the Lion’ himself was later captured in the battle of Alnwick.

Following this second siege, Odinel Umfraville made more improvements to the defences of the castle by adding a stone keep and a great hall.

History in brief: Why did Prudhoe Castle need to be strong?

Prudhoe was an important place for the English to build a castle because of the dispute over the ownership of the border lands between England and Scotland. It was an argument that lasted (on and off) for centuries.

Many great Northumbrian fortresses were attacked on the orders of the Scottish King ‘William the Lion’. He attacked Prudhoe twice in 1173 and again in 1174 when an army of 400 men set upon the castle.


How would you cope being in a castle under siege?

The Scots attacked the castle for over three days and although they destroyed the orchards and surrounding farmlands, they could not capture the castle itself. Despite not being the biggest or highest or most impressive castle in the land, Prudhoe was able to survive both sieges. When they admitted defeat, the Scots attackers reportedly declared ‘as long as Prudhoe stands, we shall never have peace.

In 1381 it was taken over from the Umfravilles by the famous and powerful Percy family, who are the Dukes of Northumberland.

Although its military importance gradually declined, Prudhoe was still the centre of a great landed estate. In the 19th century, Hugh Percy cleared areas of the castle that had become ruined over time, and built a new Regency-style manor house for the family’s land-agent where the medieval residential wing once was.

Discover what it takes to conquer a castle this summer, with our siege events across the country.

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