What I found amazing was that (at least when working with Leone) the music was written first, and was often played on set during filming. So the film was actually informed by the music, and the music is an integral and crucial part of the film. I enjoy the soundtracks to the Leone westerns as much as the action.
Listened to
Ennio Morricone: The Legendary Italian Westerns again today, I highly recommend it.
Such an incredible body of work from this man.
Rest in peace sir.