Was Theoden's speech a reference to Hamlet?

Question

In the second LOTR movie, Theoden says this before charging out at Helm's deep:

Let this be the hour when we draw swords together. Fell deeds awake. Now for wrath, now for ruin, and the red dawn. Forth, Eorlingas!

In the books, Theoden-King delivers a similar speech/poem before the Battle of Pelenor Fields:

Arise, arise, Riders of Théoden! Fell deeds awake, fire and slaughter! spear shall be shaken, shield be splintered, a sword-day, a red day, ere the sun rises! Ride now, ride now! Ride to Gondor!

In the play Hamlet, the titular character says this:

foul deeds will rise, though all the earth o'erwhelm them, to men's eyes.

I thought it was an interesting coincidence that both authors use phrases that follow a similar formula (f adjective meaning bad/evil + deeds + verb that roughly means arising). There are also parallels between the plots (After saying this, Theoden charges out to face his enemies and receives assistance from a wizard, and in turn Hamlet ventures out and has his own supernatural encounter)

Is it an intentional reference? Or is it just a coincidence – even though the phrasing sounds a bit unusual to my modern ears (people don't really think of deeds as being things that wake up or arise) maybe this sort of construction wasn't unusual in the older writings that Tolkien was inspired by?

Answer 1

No. I don't think anyone has ever tried to claim it, so I have no authoritative sources, but for starters they mean different things:

fell deeds awake is a command for some fierce/savage/deadly actions to begin

foul deeds will rise [...] to men's eyes is a warning that bad/unpleasant actions cannot be covered up and will eventually rise to the surface and be seen

Answer 2

It was a reference to the Old Norse Völuspá, not Hamlet

In The History of Middle-earth, when discussing the writing of this passage, Christopher Tolkien says:

In the remainder of The Ride of the Rohirrim' the final form was achieved in this manuscript almost word for word: the speech of Wídfara about the change in the wind, the disposition of the companies of the Rohirrim, Merry's fear that the king would quail and turn back, his great cry (with echoes of the Old Norse Völuspá) 'Arise, arise, Riders of Theoden ...', and the likening of Theoden to 'Orome the Great in the Battle of the Valar when the world was young.'
_{The History of Middle-earth volume VIII - The War of the Ring - page 353}

Christopher is likely referring to this stanza of the Völuspá (translation from here):

Brœðr muno beriaz | ok at bǫnom verða,
muno systrungar | sifiom spilla.
Hart er í heimi, | hórdómr mikill.
Skeggǫld, skálmǫld, | skildir ro klofnir.
Vindǫld, vargǫld, | áðr verǫld steypiz.
Mun engi maðr | ǫðrom þyrma.

Brothers shall fight | and fell each other,
And sisters' sons | shall kinship stain;
Hard is it on earth, | with mighty whoredom;
Axe-time, sword-time, | shields are sundered,
Wind-time, wolf-time, | ere the world falls;
Nor ever shall men | each other spare.

Incidentally, while researching this answer, I found that the TV show Vikings also used this war cry.

(It should also be noted that Tolkien would have been familiar with Hamlet, as it was one of the set texts that he had to read as an undergraduate at Oxford, and one of his final exam papers there was on Shakespeare. Tolkien also is known to have seen a performance of it in 1944 (Letters #76), has very briefly referenced it in two of his published academic lectures. However he very much didn't like Shakespeare and one of his actions as a professor was to remove him from the syllabus. It's unlikely that he would be referencing Hamlet here.)