History of Castles
A castle (from Latin castellum) is a type of fortified structure built in Europe and the Middle East during the Middle Ages by the nobility.
Scholars debate the scope of the word castle, but usually consider the private fortified residence of a lord or noble.
This is distinct from a palace, which is not fortified; from a fortress, which was not always a residence for nobility; and from a fortified settlement, which was a public defense - though there are many similarities among these types of construction.
The use of the term has varied over time and has been applied to various structures such as forts and country houses. During the years in which about 900 castles were built, they brought about a large number of forms with many different features, although some, such as curtain walls and slits, were the order of the day.