Macbeth - How much the witches were involved in his end

We are all quite aware of what the porter is talking about when saying this, relating to alcohol. But audiences back in the 1600s would have had mixed reactions. The groundlings, who paid a considerable amount less for their ticket, were the lower class and had to stand on the floor to watch the play. They would shout and scream and laugh at such comments as the one stated above. The gentry were the higher class people and would sit in the stands. They would pretend not to understand such jokes and comments of these, but deep down, you could hear their laughter. .
             The initial question asked is a perhaps yes and no answer. Macbeth was a great warrior and a high classed member of the army - "who like a good hardy soldier fought "gainst my captivity: hail brave friend;" When Duncan announces his son Malcolm as heir to the thrown. This perhaps makes the audience question the king and his decisions because the rightful heir to the thrown should indeed be Macbeth. When meeting with the witches, Macbeth is crowned Thane of Cawdor and doesn't know it yet. When meeting the witches he is told of his triumph, but another thing is said to him as well .
             Macbeth had been told by the witches that he was going to be king, and that Banquos" son was going to be King after Macbeth. If Macbeth had not conversed with these wenches, then the thoughts of Macbeth which follow from now on in the play would not have been present.
             Soon after the meeting with the witches, Macbeth wrote a letter to his wife, informing her of his meting, and all the things he had been told. I feel this was not the step in the right direction in which he needed. After reading the letter, Lady Macbeth is convinced that her husband was born to be king, and it would happen anyway it could. Lady Macbeth has a very strong personality, and on Macbeths arrival, tells him or her evil, wicked plans and her despicable ways they must kill the king! Lady Macbeth would be looked at in an evil sense now because when she is thinking of killing Duncan, she asks for evil spirits to let her do it - "come you spirits, that tend my mortal thoughts".