The Geste of Beren and Lúthien

'That may not be!' Lo! Beren spake,
and through the king's words coldly brake.
'What are thy mazes but a chain
wherein the captive blind is slain?
Twist not thy oaths, O elvish king,
like faithless Morgoth! By this ring—
the token of a lasting bond
that Felagund of Nargothrond
once swore in love to Barahir,
who sheltered him with shield and spear
and saved him from pursuing foe
on Northern battle fields long ago—
death thou canst give unearned to me,
but names I will not take from thee
of baseborn, spy, or Morgoth's thrall!
Are these the ways of Thingol's hall?'

Proud are the words, and all there turned
to see the jewels green that burned
in Beren's ring. These Elves had set
as eyes of serpents twined that met
beneath a golden crown of flowers,
that one upholds and one devours:
the badge that Finrod made of yore
and Felagund his son now bore.
His anger was chilled, but little less,
and dark thoughts Thingol did possess,

though Melian the pale leant to his side
and whispered: 'O king, forgo thy pride!
such is my counsel. Not by thee
shall Beren be slain, for far and free
from these deep halls his fate doth lead,
yet wound with thine. O king, take heed!'

(lines 1,080 to 1,111)
J.R.R. Tolkien