"So that bloody Banquo was not worthy to be compared to him"
Banquo is a character in Shakespeare’s 1606 play Macbeth.
He is a general in the King's army, as is Macbeth. The two are together when they meet the Three Witches. The witches predict that Macbeth will become king, and that while Banquo himself will never be king, his descendants will be. As Macbeth’s lust for power takes hold, he perceives Banquo as a rival and has him murdered. Later in the play, Banquo's ghost returns to haunt Macbeth.
Shakespeare borrowed the character of Banquo from Holinshed's Chronicles, a history of Britain published in 1587. Holinshed portrayed Banquo as an historical figure, an accomplice in Mac Bethad mac Findlaich’s murder of Donnchad mac Crinain. Holinshed based his work on an earlier source, the Scotorum Historiae (1526–7), by Hector Boece. While modern scholars consider Banquo and Mac Bethad as fictional characters invented by Boece, in Shakespeare's day they were considered historical figures.