But it is in the minor characters that theatrical criticism of the sources proves most helpful. The sources can provide additional clues, by either pointing out contrasts with the play or by supplying additional information or viewpoints. Then I read Holinshed's Chronicles , and found traces of a different sort of thane. The character as I conceived him suspected Macbeth of the murder, yet kept his peace, waiting to see how the witches' prophecy would turn out. On reading Shaw's production notebook, I find I was not alone in my interpretation, for in the 1955 Stratford production Banquo was even more involved in the murder plot.
Nothing is said.
Of course he is not a villain but is not a simple honest man either. He has his own particular form of ambition. Yet Banquo need not always be a stern Scot. Not until the arrival of Rosse and Angus and their news of Cawdor's death were we forced to realize that the witches might have spoken truth. Sources for the play thus provided motivations and subtext for a difficult acting passage, proving theatrically practical as well as literarily interesting.