The Caledonians (/ˌkælɪˈdoʊniənz/; Latin: Caledones or Caledonii; Ancient Greek: Καληδῶνες, Kalēdōnes) or the Caledonian Confederacy are believed to be a Brittonic-speaking (Celtic) tribal confederacy in what is now Scotland during the Iron Age and Roman eras. The Greek form of the tribal name gave rise to the name Caledonia for their territory. The Caledonians were considered to be a group of Britons, but later, after the Roman conquest of the southern half of Britain, the northern inhabitants were distinguished as Picts, thought to be a related people who would have also spoken a Brittonic language. The Caledonian Britons were thus enemies of the Roman Empire, which was the state then administering most of Great Britain as the Roman province of Britannia.
The Caledonians, like many Celtic tribes in Britain, were hillfort builders and farmers who defeated and were defeated by the Romans on several occasions. The Romans never fully occupied Caledonia, though several attempts were made. Nearly all of the information available about the Caledonians is based on predominantly Roman sources, which may be biased.