The origin and full significance of the Green Banner itself is not known. Sir Walter Scott mentions it in his novel The Fair Maid of Perth and a late 19th century painting titled "Two Men of Cluny" shows one of them holding a banner that is similar to it.

An inventory of the contents of Cluny Castle taken in 1877 lists "The Great Standard (or the Clan Banner of the Macphersons of Cluny) which has the arms of the Chief . . . emblazoned on it, being the Coat of Arms granted in 1672 by Sir Charles Erskine, Lord Lyon King-at-Arms."
There is a Clan legend that holds that no battle at which the Macphersons were present with the green banner and the chief at their head, was ever lost. The banner shown on Panel 3 was purchased in 1943 at the auction sale of the contents of Cluny Castle. Based on its appearance it is doubtful that it was ever actually carried in battle. It is possible that it is a copy of an earlier banner that is now lost.