Castles are academically defined as a private fortified residence occupied by lords, nobles and their kin during the medieval period. Typically, castles were built and owned by feudal lords for themselves and/or for their monarchs. Gothic castles and their distinctive architectural designs emerged as a stark contrast to earlier fortress designs.

Fortresses were built for pure defense alone, and fortified towns had protective structures that enabled public defense from outsiders. Examples of these pre-castle structures include Anglo Saxon Burhs, and walled cities such as Constantinople and Antioch in the Middle East.

Some of the first French and European castles built during the medieval period were created to avert invasion in addition to providing shelter for neighboring communities; they also provided dwellings for lords and noblemen. These first castles were quite basic and consisted of simple entrenchments that surrounded the castle.

Ditches were formed around the vicinity of the building, and in the centre of the enclosure rose the moat.  Castles of these earlier times relied heavily on defenses of nature, such as ditches and other natural structures. It was later on in the 12th and 13th century that a more pragmatic and scientific approach was used in castle architectural design.
Architectural designers employed towers and other innovative restructuring to increase defenses and maximize space, safety and foundation strength. Many castles were originally built from earth and timber, but later their defences and various other structures were replaced by stone. In addition to providing protected dwellings for inhabitants and serving military purposes, castles were also used as centers of administration and were symbols of power.

Gothic castles were built to include offensive and defensive fornication. These castles of the Middle Ages functioned as miniature towns with fortified walls and structures to protect their dwellers from potential attacks. Castles were composed of multiple walls reinforced by towers, which also served as refuges at various points of the circumference. Castles and keeps were built of stone and strategically placed near banks of rivers and close to valley landscaping.  

This was a departure from their previous construction on weak or artificial mounds of earth, which provided inadequate support for changes in typical architectural design. Keeps and towers eventually transformed into cylindrical shapes and dominated future plans of keep and tower buildings, as they offered the best resistance to invaders. The convex surface of these circular shapes had equal strength at every point, providing optimal circumstances for base defense.

Architectural castle design introduced the vault and intersecting arches within their construction. These supportive innovations were used heavily in castles and other military structures because of the strength and diversity they added to castle and building design. Vaults supported and bonded circular walls firmly together creating increased strength and stability.

New floors were also formed within the bounds of these new constructs, creating a more steady and durable form of flooring for the various stories. Castle design also included the pointed roof, which was more adequate at withstanding projectiles and combustibles; originally attacks with these weapons shattered the angles of the roof in old square towers and set fire to their timbers.
Aside from the military innovations that Gothic castle design introduced, many of the castles were remarkable for their aesthetically pleasing arrangements of structures, and for the richness of decorations.

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