According to Zimmer (2006), Caledonia is derived from the tribal name Caledones (or Calīdones), which he etymologises as "'possessing hard feet', alluding to standfastness or endurance", from the Proto-Celtic roots *kal- 'hard' and *φēdo- 'foot'.
[5][6] According to Historia Brittonum, the site of the seventh battle of the legendary King Arthur was a forest in what is now Scotland, called Coit Celidon in early Welsh.
[citation needed] The modern use of "Caledonia" in English and Scots is either as a historical description of northern Britain during the Roman era or as a romantic or poetic name for Scotland as a whole.
In music, "Caledonia" is a popular Scottish patriotic song and folk ballad written by Dougie MacLean in 1977 and published in 1979 on an album of the same name; it has since been covered by various other artists, most notably Frankie Miller and Van Morrison.
[12][13] Ptolemy's account in his Geography also referred to the Caledonia Silva, an idea still recalled in the modern expression "Caledonian Forest", although the woods are much reduced in size since Roman times.