Caledonia was the Latin name used by the Roman Empire to refer to the part of Scotland that lies north of the River Forth, which includes most of the land area of Scotland. Today, it is used as a romantic or poetic name for all of Scotland. During the Roman Empire’s occupation of Scotland, the area they called Caledonia was physically separated from the rest of the island by the Antonine Wall. The Romans several times invaded and occupied it, but unlike the rest of the island, it remained outside the administration of Roman Britain.
Latin historians, including Tacitus and Cassius Dio, referred to the territory north of the River Forth as “Caledonia”, and described it as inhabited by the Maeatae and the Caledonians (Latin: Caledonii). Other ancient authors, however, used the adjective “Caledonian” more generally to describe anything pertaining to inland or northern Britain. The name is probably derived from a word in Common Brittonic.
