This is a (greatly) shortened version of the tale of Luthien. I’m not sure what type of poem it is, although originially it was supposed to be Linnod, a type of Elvish poetry. I am pretty sure I took poetic liberty, or whatever, several times
Frightened Luthien now fled, but swiftly after her he sped.
And his chase was of avail, he followed, naming her Nightengale.
Now she stopped, caught by his voice, and forever faced the doom of her choice.
He came to her and was entranced, by the beauty he beheld by chance.
Together they went to Thingol King, but he sent Beren for an artifact greater than the ring.
“Bring me a Silmaril”, he commanded, and she will be yours when to me it is handed.
On he went, to his journey, and he met people worse than Bill Ferny.
Luthien also, wanted to go, but Thingol, her father, said no.
Never the less, she went away, regardless of anything he could say.
Their journey is told of elsewhere, but I can say that it would give most people a scare.
Eventually they came to Angband, after going through Sauron’s dungeons and Nargothrond.
They came disguised as creatures of Morgoth, their guise fooled all, even Carcharoth.
Now they reached the Dark Lord himself, and appeared as they were, mortal and elf.
She sang a song, willing him to sleep, and it worked, on the entire keep.
Taking now the blade of Telchar, he cut free a silmaril, but the knife gained quite a scar.
It broke at the tip and struck Morgoth’s cheek, everyone woke and suddenly they felt very meek.
They ran away, with the jewel, but Carcharoth ate it, the fool.
It burned his insides and he ran away, and the Great Hunt took place and to the Good side it did sway.
Now Thingol finally had his gem, and Luthien finally wed Beren.
They are known to have gone to an island, and that brings the tale to its final end.