<P> At a banquet, Macbeth invites his lords and Lady Macbeth to a night of drinking and merriment . Banquo's ghost enters and sits in Macbeth's place . Macbeth raves fearfully, startling his guests, as the ghost is only visible to him . The others panic at the sight of Macbeth raging at an empty chair, until a desperate Lady Macbeth tells them that her husband is merely afflicted with a familiar and harmless malady . The ghost departs and returns once more, causing the same riotous anger and fear in Macbeth . This time, Lady Macbeth tells the lords to leave, and they do so . </P> <P> Macbeth, disturbed, visits the three witches once more and asks them to reveal the truth of their prophecies to him . To answer his questions, they summon horrible apparitions, each of which offers predictions and further prophecies to put Macbeth's fears at rest . First, they conjure an armoured head, which tells him to beware of Macduff (IV. i. 72). Second, a bloody child tells him that no one born of a woman shall be able to harm him . Thirdly, a crowned child holding a tree states that Macbeth will be safe until Great Birnam Wood comes to Dunsinane Hill . Macbeth is relieved and feels secure because he knows that all men are born of women and forests cannot move . Macbeth also asks whether Banquo's sons will ever reign in Scotland: the witches conjure a procession of eight crowned kings, all similar in appearance to Banquo, and the last carrying a mirror that reflects even more kings . Macbeth realises that these are all Banquo's descendants having acquired kingship in numerous countries . After the witches perform a mad dance and leave, Lennox enters and tells Macbeth that Macduff has fled to England . Macbeth orders Macduff's castle be seized, and, most cruelly, sends murderers to slaughter Macduff, as well as Macduff's wife and children . Although Macduff is no longer in the castle, everyone in Macduff's castle is put to death, including Lady Macduff and their young son . </P> <P> Meanwhile, Lady Macbeth becomes racked with guilt from the crimes she and her husband have committed . At night, in the king's palace at Dunsinane, a doctor and a gentlewoman discuss Lady Macbeth's strange habit of sleepwalking . Suddenly, Lady Macbeth enters in a trance with a candle in her hand . Bemoaning the murders of Duncan, Lady Macduff, and Banquo, she tries to wash off imaginary bloodstains from her hands, all the while speaking of the terrible things she knows she pressed her husband to do . She leaves, and the doctor and gentlewoman marvel at her descent into madness . Her belief that nothing can wash away the blood on her hands is an ironic reversal of her earlier claim to Macbeth that "(a) little water clears us of this deed" (II. ii. 66). </P> <P> In England, Macduff is informed by Ross that his "castle is surprised; wife and babes / Savagely slaughter'd" (IV. iii. 204--05). When this news of his family's execution reaches him, Macduff is stricken with grief and vows revenge . Prince Malcolm, Duncan's son, has succeeded in raising an army in England, and Macduff joins him as he rides to Scotland to challenge Macbeth's forces . The invasion has the support of the Scottish nobles, who are appalled and frightened by Macbeth's tyrannical and murderous behaviour . Malcolm leads an army, along with Macduff and Englishmen Siward (the Elder), the Earl of Northumberland, against Dunsinane Castle . While encamped in Birnam Wood, the soldiers are ordered to cut down and carry tree limbs to camouflage their numbers . </P>

Where did the idea of macbeth come from