A castle is a type of fortified structure built during the Middle Ages predominantly by the nobility or royalty and by military orders. 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 royalty or nobility; from a pleasance which was a walled-in residence for nobility, but not adequately fortified;and from a fortified settlement, which was a public defence – though there are many similarities among these types of construction. Use of the term has varied over time and has also been applied to structures such as hill forts and 19th-20th century homes built to resemble castles. Over the approximately 900 year