Concentric castles, which were sometimes erected on a rise and sometimes surrounded by a moat, were far bigger than earlier motte and bailey designs and could never be built on man-made mounds. There would be a core enclosure of stone walls and towers, followed by one or more surrounding walls with towers as well. The final stage was always a royal palace built within the walls.
They were usually built for the king by his military commander as a statement of power and as a place to hold court. The earliest known example is the Concentric Castle of Urartu in Armenia, which was built around 1450 B.C. This was several hundred years before the first British or French castles were built.
The walls of these castles could be quite thick (up to six feet in some cases), but they were also fragile. If the threat had disappeared then so had the reason for having the castle built in the first place. That's why most of them were abandoned after a few years.
Some remain in use today. For example, the wall around the Old City of Jerusalem was probably built for defense rather than oppression because it prevents people from entering the city limits except via one of the three main gates.
The term "concentric castle" comes from the shape of the walls when they're looked at from above; they're like many small circles joined together.
Because of the many walls erected around the central tower, concentratic castles were difficult to conquer and penetrate. Moats, battlements, and gatehouses provided extra security. The overall effect was that a concentric castle was more defensible than an open ringwork fort.
Concentric castles first appeared in Europe around 1150 and became popular throughout much of medieval times. They are found everywhere from England to Serbia. The best-known example is the Tower of London.
Concentric castles use earthworks and standing stones instead of stone or brick for their defense. They are often found near large settlements or important resources such as mines or fishing boats.
The word "concentric" comes from the Latin word meaning "around a center" or "in a circle". Although they look like circles, concentric castles are actually based on a hexagonal pattern with six towers each pointing in a different direction. The corners of this pattern are reinforced with extra defenses such as additional walling or moats.
Often several concentric rings are built one over another. For example, the outer ring of the castle might be built using wood but the inner ring would be made out of stone. This allows people to rebuild areas of the castle destroyed in war or natural disasters without affecting the main structure or interior rooms.
Motte and bailey castles were a form of early fortification. A yard, or bailey, was erected adjacent to an earth mound, or motte, with a tower or watchtower on top. Stables, a hall, workshops, a spring, and a church were all common features of a bailey. The motte and bailey were encircled by a ditch and secured by a palisade barrier.
The word "motte" comes from the French word "moit," which means "mountain." Therefore, a motte is a raised earth mound used for defense purposes.
A bailey is a flat area inside the walls of a castle made up of open fields that could be used for farming or grazing. Baileys are often surrounded by a ditched wall called a berm. In some cases, they may have their own towers or buildings within the enclosure. As we'll see in the next question, baileys provide protection for people as well as structures.
Castles were used for defense against invaders who would want to enter the country illegally or enemies who might want to destroy a town but not its defenses first. They also provided refuge for those who lived in the town or country surrounding the castle if the city or village was attacked. Castles were important for keeping out invaders and providing safety for citizens.
Royalty refers to the rulers of a country or state.
Stone walls and towers replaced the timber defenses of motte and bailey castles. Because stone is more robust and resistant than wood, it became the chosen material for castle construction. Stone castles were higher and provided superior defense against attack, fire, and cold rainy weather. The new castles were also easier to defend - soldiers could better see approaching enemies.
They also tended to be larger and house more people. A stone tower could be much taller and have more rooms than a wooden one. The great hall was often large enough to serve as a church in smaller towns. It could hold hundreds of people with ease.
In addition, they were usually well-sited within their protective enclosures. A commander could watch for enemy troops from his castle battlements or from an upper room. He could also signal to loyal subjects in other parts of the kingdom by lighting fires on hilltops or cliff faces. These warnings allowed King's men to take precautions or escape if necessary.
Finally, stone is harder to mine than earth. This means that stone castles could be built more quickly than those made of earth. They also remained standing after wars or disasters destroyed other buildings. By the late 11th century, almost all English castles were made of stone.