A castle is a type of fortified structure built in Europe and the Middle East during the Middle Ages by nobility. Scholars debate the scope of the word castle, but usually consider it to be 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 defence – though there are many similarities among these types of construction.
