Written in 1824 by a local Anglican vicar, the song is a telling of events (with a few inaccuracies) that took place in 1688. Trelawny, who the anthem is named after and the main figure in the song, is somewhat of a Cornish national hero. A Protestant bishop imprisoned by the Catholic king James VII of Scotland / James II of England, he was found acquitted of seditious libel after an uprising and war.
Trelawney is an unofficial, local anthem, since Cornwall is a part of the United Kingdom. As well, no official anthem has been declared by any Cornish governmental body. As such, it is hard to distinguish what is the true anthem of Cornwall. Another song that also lays claim as the “Cornish national anthem” is “Bro goth agan tasow” (“Old Land of our Fathers”), using the same melody as Brittany‘s anthem (another Celtic area in the region).
Special thanks to: Ken Westmoreland, David Ricketts, and Bert H de la Houssaye for some of this information, to Yan Cross for the Cornish lyrics, and to “Dr. Drake” for translation assistance on “Bro goth agan tasow”.