Duncan announces that Malcolm is named as his successor to the throne after him and will be given the title of Prince of Cumberland.
Duncan gives Malcolm the title of Prince of Cumberland. Supposedly this marks him as the heir apparent. In actuality there never was such a title as Prince of Cumberland anywhere. Although heirs apparent were indicated in eleventh-century Scotland, they still had to be elected to the throne.
Malcolm, King Duncan's son, is proclaimed Prince of Cumberland in Act I Scene 4
Macbeth is Duncan's cousin, as in the play duncun say's "o worthiest cousin" to Macbeth in act 1 scene four
Duncan's older son Malcolm. He is named Prince of Cumberland in Act I, Scene 5, Lines 44-45.
In Shakespeare's Macbeth, King Duncan had two sons, Malcolm and Donalbain. Donalbain leaves for Ireland in Act II and that's the last we hear of him. Malcolm ends up succeeding Macbeth.
What happened to Malcolm is that he later comes back home.And he soon becomes King in place of his father who was killed by Macbeth in act 2....
Malcolm's title is Prince of Cumberland. He is named Duncan's heir apparent. At the time, the eldest son was NOT automatically the next in line for the throne. Macbeth, as the most experienced and respected soldier, expects to be named, but Duncan passes him over for the feckless Malcolm.
At the end of the Shakespearean play 'Macbeth', Scotland was at war with England. The first act had begun with the defensive war of Scotland under King Duncan I [d. August 14, 1040] against invading Norwegians and traitorous Scotsmen. So too did the last act begin with the defensive war of Scotland under Macbeth [c. 1014-August 15, 1057] against invading Englishmen and discontented Scotsmen.
In Act III Scene 6 Lennox and another Lord discuss their deep suspicions that Macbeth is responsible for the murders of Banquo and Duncan. I hope that is the Scene 6 you had in mind; there is one in Act I and another in Act V. In the one in Act 5, Malcolm's army gets rid of its camouflage.
He did not exactly directly announced that a certain person will be heir to his throne. However, after he blesses and acknowledged the bravery of Macbeth and Banquo, he announces that his son Malcolm is now Prince of Cumberland, which only means that he can be the next king. Read act 1 scene 4.
In Act 1, Scene 4 of "Macbeth," Banquo is honored by being named a nobleman and receiving the title of the Thane of Lochaber. Malcolm, the Prince of Cumberland, is also honored by being declared heir to the Scottish throne by King Duncan.
Malcolm and Donalbain first react to the news of their father's murder with confusion, then with a kind of dull amazement that they are not capable of showing grief at this time. Macbeth is going on about how overcome he was with anger on seeing Duncan dead, and Lady Macbeth is keeling over in a faint, and Malcolm and Donalbain say nothing. But their grief is genuine, and that of the Macbeths is not. This feeling is shortly replaced by fear, the fear that they are next on the list. That was probably true enough.