 Shakespeare 's Lady Macbeth appears to be a composite of two personages found in the account of King Duff and in the account of King Duncan in Holinshed 's Chronicles ( 1587 ) . In the account of King Duff , one of his captains , Donwald , suffers the deaths of his kinsmen at the orders of the King . Donwald then considers regicide at " the setting on of his wife " , who " showed him the means whereby he might soonest accomplish it . " Donwald abhors such an act , but perseveres at the nagging of his wife . After plying the King 's servants with food and drink and letting them fall asleep , the couple admit their confederates to the King 's room , where they then commit the regicide . The murder of Duff has its motivation in revenge , rather than ambition . 
