Medieval Castle Types

Castles in Medieval Europe fell into 3 main categories: Motte and Bailey, Stone Keep, and Concentric.

While innumerable variations and individualizations of castles existed, these 3 types of castles dominated the Medieval period in northern Europe. Castles are defined as 'fortified dwellings of the King or Lord of the territory in which [they] stood' (Encyclopedia Britannica). Distinctly different than forts, which were used by the military, and palaces, which were unfortified estates, castles were used by lords to protect their lands and showcase their wealth and power.

Castles became popular in northern Europe around the 9th century after the fall of the Carolingian empire and alongside the rise of Feudalism. Feudalism fundamentally changed the fabric of northern European culture between the 9th and 15th centuries, upending the existing legal, economic, military, and cultural customs of the era. Under the hierarchy of the feudal system, the Crown granted land to the nobility in exchange for loyalty and military servitude. Nobility then allowed peasants, or serfs, to work and live on their land in exchange for protection and a share of their labor.

The Feudal system incentivized loyalty to one's Lord, who had absolute control over the lands they were granted which were often of no fixed size. Lords were powerful and influential figures and could, in some cases, control multiple estates. This led to conflicts of interest and, in the case of the Baron's Revolt of 1215, complete refusal of the Crown's authority. The feudal system, whose base word fede means hostility in old English (Oxford Languages), incentivized conflict which led to unrest and increased fighting between Lords who sought to both expand into new territory and retain power over that which they had already conquered. Building a castle was not only a show of wealth and power but served as a necessary stronghold to protect the Lords, their families, riches, and subjects.

Through the centuries, new castles were built while existing ones were added onto. Most castles have a rich history of different Lords making additions to the fortifications while being influenced by new designs that offered increased security and luxury. Monarchs and Lords alike showcased their wealth and power throughout the centuries by building castles, creating incredible and diverse structures that still stand today.

Motte and Bailey

The first Motte and Bailey castles were recorded in the Norman region of modern-day France in the 9th century. The design quickly spread throughout northern Europe as the Normans invaded neighboring territories. The castle design offered a relatively simple and easy to construct design that could be completed in a few months by unskilled peasant laborers.

This design featured a wooden fort, which later evolved into the Keep, which sat atop an earthen mound or motte, which could be natural or human-formed. An enclosed courtyard, or bailey, sat at the base of the motte. The castle was surrounded by a ditch or moat and palisade, a wall constructed from wooden stakes.

While a simple construction, the Motte and Bailey provided robust protection against attackers. The ditch and palisade served as a first line of defense while the motte gave defenders the high ground and neutralized the small calvary units that were popular at the time.

Stone Keep

Construction of stone keep castles increased in the 11th and 12th centuries in Europe. They offered superior protection compared to the wood construction of Motte and Bailey castles but were much more expensive and required more time to build. The increased cost came from the stone material, which needed to be mined and transported, as well as the employ of skilled stone masons and craftsmen to design and build the castles.

The increased cost did have its advantages, however. Stone castles became another opportunity to flaunt one's wealth. The exterior walls of the Keep were often decorated with ornate carvings and architectural details that were very expensive to create.

Thick walls around the base of the keep (some 20+ ft thick) also allowed for higher construction. Stone keeps were often several stories tall, fireproof, and nearly impenetrable to outside forces. They also lasted longer, as wood keeps and palisades eventually rotted.


Concentric castles succeeded Stone Keep castles and became popular during the 12th and 13th centuries. These castles were massive and featured two sets of tall, strong walls called curtains to provide multiple layers of defense. Keeps became redundant, as the enemy was never meant to breach the outer wall.

The walls were built with many defensive features such as towers, arrow slits, and embrasures to protect defenders from incoming fire. The outer wall was also shorter than the inner wall to allow for two sets of archers to fire at attackers simultaneously. The baileys of these castles were also large enough to hold multiple garrisons of troops, who provided further protection.

The massive size and complexity of these castles meant that they were incredibly expensive to build, with only Kings and the wealthiest Lords able to afford them. They also took much longer to build than their predecessors, in some cases requiring decades to complete the design and construction.

The end of an era

The era of the Medieval castle came to an end with the rise of gunpowder and firearms in the 15th and 16th centuries. The stone walls of castles were no match for cannons, which quickly and easily laid waste to the structures under siege. Castles gave way to military fortresses and palaces, which separated military and domestic architecture. Fortified military structures became known as forts and were under the direct control of the Monarch. The domestic dwellings of Kings and Nobles became known as palaces, which were unfortified mansions and manor houses.

The separation of military structures and the homes of the Nobility is no more evident than in the designs of Windsor Castle and Buckingham Palace. These buildings were the primary dwellings of British Monarchs during the 11th and 19th centuries (respectively), and varied greatly in their design.

Windsor Castle began as a Motte and Bailey design built by William the Conqueror in the 11th century. It has been expanded over time, but still maintains the defensive design of a medieval castle.

Buckingham Palace was built in the mid 19th century and as the primary residence and working building of the current Monarch, features a more refined and stately design built for comfort and reception.

About the author

Bryan Manis

Bryan is the Founder and President of Tower & Keep. Researcher by day and designer/entrepreneur by night, his vision is to give life to the unseen and forgotten stories all around us.


Feudalism  by Mark Cartwright for World History Encyclopedia. 22 November 2018.The Medieval Castle, Four Different Types, History on the Net. 03 December 2021. Castle Types, Encyclopædia Britannica. 05 December 2021. Norman People, Encyclopedia Britannica. 04 September 2015. Medieval Castles, The National Archives United Kingdom. Castle Keep, Mark Cartwright for World History Encyclopedia. 14 June 2018. Castle Architecture, Encyclopedia Britannica. 18 Nov. 2021Windsor Castle, Royal Collection Trust. Royal Residences: Buckingham Palace, Royal.UK. Medieval: Warfare, English Heritage.


Castle Types illustrations, "Castle Types" by Encyclopædia Britannica. 13 December 2021.

Windsor Castle "Windsor Castle, Berkshire, from the Long Walk" by JackPeasePhotography is licensed with CC BY 2.0. To view a copy of this license, visit

Buckingham Palace "Buckingham Palace" by dbaron is licensed with CC BY-SA 2.0. To view a copy of this license, visit