Though placed so high, Macbeth and his queen could not forget the prophecy of the weird sisters, that, though Macbeth should be king, yet not his children, but the children of Banquo, should be kings after him.  The thought of this, and that they had defiled their hands with blood, and done so great crimes, only to place the posterity of Banquo upon the throne, so rankled within them, that they determined to put to death both Banquo and his son, to make void the predictions of the weird sisters, which in their own case had been so remarkably brought to pass.

For this purpose they made a great supper, to which they invited all the chief thanes; and, among the rest, with marks of particular respect, Banquo and his son Fleance were invited.  The way by which Banquo was to pass to the palace at night, was beset by murderers appointed by Macbeth, who stabbed Banquo; but in the scuffle Fleance escaped.  From that Fleance descended a race of monarchs who afterwards filled the Scottish throne, ending with James the sixth of Scotland and the first of England, under whom the two crowns of England and Scotland were united.

At supper the queen, whose manners were in the highest degree affable and royal, played the hostess with a gracefulness and attention which conciliated every one present, and Macbeth discoursed freely with his thanes and nobles, saying, that all that was honourable in the country was under his roof, if he had but his good friend Banquo present, whom yet he hoped he should rather have to chide for neglect, than to lament for any mischance.  Just at these words the ghost of Banquo, whom he had caused to be murdered, entered the room, and placed himself on the chair which Macbeth was about to occupy.  Though Macbeth was a bold man, and one that could have faced the devil without trembling, at this horrible sight his cheeks turned white with fear, and he stood quite unmanned with his eyes fixed upon the ghost.  His queen and all the nobles, who saw nothing, but perceived him gazing (as they thought) upon an empty chair, took it for a fit of distraction; and she reproached him, whispering that it was but the same fancy which had made him see the dagger in the air, when he was about to kill Duncan.  But Macbeth continued to see the ghost, and gave no heed to all they could say, while he addressed it with distracted words, yet so significant, that his queen, fearing the dreadful secret would be disclosed, in great haste dismissed the guests, excusing the infirmity of Macbeth as a disorder he was often troubled with.

To such dreadful fancies Macbeth was subject.  His queen and he had their sleeps afflicted with terrible dreams, and the blood of Banquo troubled them not more than the escape of Fleance, whom now they looked upon as father to a line of kings, who should keep their posterity out of the throne.  With these miserable thoughts they found no peace, and Macbeth determined once more to seek out the weird sisters, and know from them the worst.