The witches eventually lead Macbeth to his demise, and they hold a striking resemblance to the three Fates of classical mythology.

Other possible sources, apart from Shakespeare, include British folklore, contemporary treatises on witchcraft as King James VI of Scotland's Daemonologie, the Witch of Endor from the Bible, the Norns of Norse mythology, and ancient classical myths of the Fates: the Greek Moirai and the Roman Parcae.

Upon killing the king and gaining the throne of Scotland, Macbeth hears them ambiguously predict his eventual downfall.

Some have exaggerated or sensationalised the hags, or have adapted them to different cultures, as in Orson Welles's rendition of the weird sisters as voodoo priestesses.

Holinshed described the future King Macbeth of Scotland and his companion Banquo encountering "three women in strange and wild apparell, resembling creatures of elder world" who hail the men with glowing prophecies and then vanish "immediately out of their sight".

[3] Holinshed reported that "the common opinion was that these women were either the Weird Sisters, that is [...] the goddesses of destiny, or else some nymphs or fairies endued with knowledge of prophecy by their necromantical science.

"[3] Another principal source was the Daemonologie of King James published in 1597 which included a news pamphlet titled Newes from Scotland that detailed the infamous North Berwick witch trials of 1590.

Not only had this trial taken place in Scotland, witches involved confessed to attempt the use of witchcraft to raise a tempest and sabotage the very boat King James and Queen Anne were on board during their return trip from Denmark.

[4] The news pamphlet states: Moreover she confessed that at the time when his Majesty was in Denmark, she being accompanied with the parties before specially named, took a Cat and christened it, and afterward bound to each part of that Cat, the cheefest parts of a dead man, and several joints of his body, and that in the night following the said Cat was conveyed into the midst of the sea by all these witches sailing in their riddles or Cues as aforesaid, and so left the said Cat right before the town of Leith in Scotland: This done, there did arise such a tempest in the Sea, as a greater has not been seen, which tempest was the cause of the perishing of a Boat or vessel coming over from the town of Brunt Island to the town of Leith, of which was many Jewels and rich gifts, which should have been presented to the current Queen of Scotland, at her Majesty's coming to Leith.

Again it is confessed, that the said christened Cat was the cause that the King Majesty's Ship at his coming forth of Denmark, had a contrary wind to the rest of his Ships, then being in his company, which thing was most strange and true, as the King's Majesty acknowledgesThe concept of the Three Witches themselves may have been influenced by an Old Norse skaldic poem,[5] in which twelve valkyries weave and choose who is to be slain at the Battle of Clontarf (fought outside Dublin in 1014).

[14] In Act 3, Scene 5 (believed to not be written by Shakespeare),[14] the Witches next appear and are reprimanded by Hecate for dealing with Macbeth without her participation.

In Act 4, Scene 1, the Witches gather and produce a series of ominous visions for Macbeth that herald his downfall.

[17] Horace Walpole created a parody of Macbeth in 1742 entitled The Dear Witches in response to political problems of his time.

[18] Orson Welles' stage production of Macbeth sets the play in Haiti, and casts the witches as voodoo priestesses.

In Eugène Ionesco's satirical version of the play Macbett (1972), one of the witches removes a costume to reveal that she is, in fact, Lady Duncan, and wants to be Macbeth's mistress.

[21] Drawings contained in Holinshed's Chronicles, one of the sources Shakespeare used when creating the characters, portray them as members of the upper class.

Shakespeare seems to have diverted quite a bit from this image, making the witches (as Banquo says): withered, and so wild in their attire, That look not like th' inhabitants o' th' earth ... each at once her choppy fingers laying upon her skinny lips.

Both brothers' work influenced many later artists by removing the characters from the familiar theatrical setting and placing them in the world of the story.

In this particular painting he uses lightning and other dramatic effects to separate Macbeth and Banquo from the witches more clearly and communicate how unnatural their meeting is.

Silhouettes of the victorious army of Macbeth can be seen celebrating in the background, but lack of space necessitates the removal of the barren, open landscape seen in Fuseli's earlier paintings for the Boydell Shakespeare Gallery of the same scene.

He said, "when Macbeth meets with the witches on the heath, it is terrible, because he did not expect the supernatural visitation; but when he goes to the cave to ascertain his fate, it is no longer a subject of terror."

Each group enters separately at the start of the opera for the scene with Macbeth and Banquo; after the men's departure, they have a chorus of triumph which does not derive from Shakespeare.

[26] In Henry Purcell's opera Dido and Aeneas with libretto by Nahum Tate, the Sorceress addresses the two Enchantresses as "Wayward Sisters," identifying the three of them with the fates, as well as with the malevolent witches of Shakespeare's Macbeth.

In Wyrd Sisters, a Discworld fantasy novel by Terry Pratchett these three witches and the Globe Theater, now named "The Dysk", are featured.

[28](pp 129-130) Throne of Blood, a Japanese version filmed in 1958 by Akira Kurosawa, replaces the Three Witches with the Forest Spirit, an old hag who sits at her spinning wheel, symbolically entrapping Macbeth's equivalent, Washizu, in the web of his own ambition.

Roman Polanski's 1971 film version of Macbeth contained many parallels to his personal life in its graphic and violent depictions.

The witches are replaced by three hippies who give Joe McBeth drug-induced suggestions and prophecies throughout the film using a Magic 8 Ball.

"[30] In Joel Coen's 2021 film The Tragedy of Macbeth, British actress Kathryn Hunter plays all three witches.

Portrayed as old, grossly deformed women who wield ancient, powerful magic, they are malicious characters, able to shapeshift (among others, into a flock of crows), and pose challenges to the game's protagonists.

More playfully, Rowling also invented a musical band popular in the Wizarding world called The Weird Sisters that appears in passing in several books in the series as well as the film adaptation of Harry Potter and the Goblet of Fire.