In The Merry Wives of Windsor Sir John Falstaff dresses up as “Herne the Hunter” and is positioned beneath an oak tree decked out in horns, just like a stag. Herne is Shakespeare’s creation, he is a ghost said to haunt Windsor Great Park—he does ghostly things like shake chains and turn cow’s milk to blood. In Wives Falstaff’s main objective is to cuckold another man; in his attempts, he ends up smuggled out of his lover’s house in dirty linen (to be dumped in a river) and—dressed as an old witchy woman—beaten by his lover’s husband as “a woman”. To have Falstaff appear in horns is a joke within the play because Falstaff is the one trying to cuckold someone else, but it is he who “wears the cuckold’s horns” at the end—just literally.
As noted, Merlin is synonymous with the horned stag god Cernunnus—the hunter (Cernunnus, Hernunnus, Herne; the hunter’s horn, the horny hunter). Merlin is also a figure like Falstaff (Shakespeare’s only recurrent character)—he is a trickster and a rogue who has unfortunate tumbles (he avenges himself against his wife’s lover and then promptly falls into a river). Falstaff is the same: obese, drunk, a whoremonger, a gambler, and a rogue who hangs out with petty thieves and criminals. He is the same type as Merlin: he is the Mercurial trickster—and that is why he is such a notable figure in Shakespeare’s work; he is the god Cernunnus returned, he is Merlin too. His role is to “make the magic work”—the magic of language, the spells.
In A Midsummer Night’s Dream, Shakespeare speaks about the fairy queen with her orbs—just like the orbs I saw at Hartsfell, Merlin’s retreat and Britain’s second initiatory site. Shakespeare also knew about these secrets; he knows that “the horns”—also referenced in Lear as “the snail’s horns”—stand for the Mercurial hermaphrodite, he who unites the masculine and feminine principles in one and becomes awakened.