Castles and forts are always confused with each other because both structures are fortified.
England has a monarchial system of governance, ruled by kings which prompted big habitats to be built.
Palaces are the homes of top officials who work in a certain government.
Some individuals usually mistake a castle for a mansion, both words are different and serve different purposes.
In earlier centuries, castles were known to be set up in each kingdom, to serve as a dwelling place of a King, and his family.