The Castle Keep

The Meaning and Origin of the word 'Keep', 'Donjon' and Dungeon!
The meaning and origin of the castle keep explain this unusual word! The word 'donjon' was originally used to describe the castle keep (the tower which was built on top of the motte). The origins of the word 'Donjon' was derived from a Latin word meaning 'Dominating Point'. Later the word 'Donjon' was changed to 'Keep'. The word 'Keep' means "that which keeps or protects - the strongest and securest part of a castle, often used as a place of residence by the lord of the castle". The word 'Keep' also means "To hold, not to let go of, to retain in one's power or possession". The term 'castle keep' is therefore explained! The term 'Donjon' was not lost - it was a derivative for the word 'Dungeon' - the Nobles moved from the towers to more easily accessible living quarters and important prisoners were held in the 'donjons'. As time passed these towers for prisoners ceased to be built and prisons were built below ground level - the dungeon!

The Castle Keep

• Attacking and Defending medieval Norman Stone built Castles
• The purpose of Norman Stone Castles ?
• What did Norman Norman Stone Castles look like - the Architecture?
• What type of stone was used to build castles?

The Castle Keep

Converting a Wooden Castle Keep to a Stone Castle Keep!
Many of the initial wooden constructions of the Motte and Bailey Castles were strongly fortified by converting them to stone castles. The wooden castle keep featured in the early Motte and Bailey castles was re-built as a stone keep. The first development and fortification of the castle keep was to raise the timber buildings on stone walls and once this was complete to entirely re-build the Castle Keep (tower) in stone. Thus emerged the first Stone Castle keeps of the Medieval Era - including, of course, the famous Tower of London.

The Square Stone Keep
The big Norman Stone Castles were expensive and time consuming to build. The Square Stone Keep evolved as a more compact type of castle stronghold than the Motte and Bailey castle designs. The Square Stone Keep provided an impressive fortress, smaller and more compact than their larger counterparts but never-the-less a secure dwelling place for a Norman noble and his family. Robert, Lord of Belleme (Robert de Belleme 1052-1130) was a chief architect and builder of the stone castle keep used by William the Conqueror. The Square Stone Keeps were built as follows:

• Usually built on the ground of the Bailey - rather than on top of the mound
• The Mottes were becoming dispensable - it was difficult to provide a stable foundation for a stone castle
• The Keeps ranged from two to four storeys in height
• Thick strong walls, often strengthened further by buttresses
• Stone curtain walls were constructed anywhere between 20 and 40 feet high and 7 to 20 feet thick
• A gateway to a staircase leading up to the first storey
• A Drawbridge was introduced
• Each storey divided by walls into separate rooms
• Higher storeys accessed by spiral staircases built at the corners of the Keep
• The Keep housed a principle hall on the first storey
• The Keep housed a well
• A Garderobe, or latrine, was also provided
• Windows were set in thick walls in the upper storeys
• A Chapel was usually built into the Keep
• The ground floor acted as a storeroom
• The top floor of the castle keep often contained the kitchens and ovens. Should the castle keep come under attack boiling water, burning oil, or hot sand could be prepared!

The Tower of London - the most famous Square Keep (The White Tower)
William the Conqueror built the White Tower. It is the most famous Castle Keep in Great Britain and situated on north bank of the Thames River. Construction of this famous castle keep started in 1078.

• The White Tower is 90 feet high
• The thickness of the walls ranged from 15 feet at the base to almost 11 feet in the upper storeys
• Above the battlements four turrets were built
• The name of the Norman Master Builder who built the square keep was Gundulf
• The White Tower was built by Norman masons but the labourers were English (Anglo-Saxon)
• The East and South sides of the White Tower were protected to the by the old Roman London City walls
• The entrance to the Tower is on the first floor accessed via a removable staircase, designed to make invasion of the White Tower more difficult
• The first structure on the site was a Motte and Bailey castle
• The White Tower was commissioned by William the Conqueror in 1078 and completed in 1097
• The North and West sides of the White Tower were protected by ditches

The Square Keep changes to a Round Keep!
The first type of castle keep was square. The square Castle Keep proved to problematical as it was subject to assault by mining. Tunnels were mined leading to a weak part of the stone castle (the corners of  the square stone keep). The corners were also subject to blind spots - an attacker could take cover behind the corners. These defensive problems led to a change of architecture towards the end of the 12th century and the development of round stone castles and keeps began. The round castle keep afforded no screen to the enemy.

The Shell Castle Keep
The shell castle keep was developed because the motte (mound) on which the castle was to be built could not bear the weight of a solid stone tower. This process was called 'Revetting the Motte'. The principle of 'Revetting the Motte' was to prevent the Motte collapsing under the heavy weight of a stone keep. The shell castle keep was created by building a stone wall which completely surrounded the upper part of the motte (mound), similar to the old palisades. These types of keeps were hollow and distributed the weight. The shell castle keep walls were strengthened by the addition of wall towers and buttresses. The walls of the Shell Castle Keep were between 8 and 10 feet thick and could range from 20 to 25 feet in height! This type of shell was not fragile! The shell keep walls were often strengthened even further by the addition of gatehouses, wall towers and buttresses. The wall acted as a defence during the re-building process. The Lord of the shell keep castle, and his family, were usually housed within the circular area enclosing the keep.

The Castle Keep
The development of the Castle Keep was important as the most protected part of the castle. The square shaped stone castle keep is the dominant feature of many of the castles in England which were built by the Normans, and one of the most commonly recognised parts of a Castle - the information provided on this page charts the objective and development of the English castle keep.

Castle Keep

Norman Pre-Built Timber Castles
Motte and Bailey Castle Layout
Motte and Bailey Castles - Attack & Defence
Famous Motte and Bailey Castles
Life in a Motte and Bailey Castle
Norman Medieval Stone Castles
Norman Castles
Romanesque Architecture