The title refers to the Hebridean Islands which are thought by some to represent Ultima Thule, or The Edge of The World. Chisholm very probably got the idea for this whole group of preludes from Amy Murray, an American, from whose book Father Allan’s Island he got all the tunes except for the prelude Rudha Ban.
Orchestrated versions of nine of the preludes were first performed by the BBC Scottish Orchestra in 1949, and conducted by Chisholm himself.
These are much more than simple settings of traditional melodies. As the term “Preludes” implies, they are more in the form of meditations or improvisations on some aspect of a melody which may only appear in full once in the whole piece.