Villanelle:

The highly structured villanelle is a nineteen-line poem with two repeating rhymes and two refrains. The form is made up of five tercets followed by a quatrain. The first and third lines of the opening tercet are repeated alternately in the last lines of the succeeding stanzas; then in the final stanza, the refrain serves as the poem's two concluding lines. Using capitals for the refrains and lowercase letters for the rhymes, the form could be expressed as: A1 b A2 / a b A1 / a b A2 / a b A1 / a b A2 / a b A1 A2.

Strange as it may seem for a poem with such a rigid rhyme scheme, the villanelle did not start off as a fixed form. During the Renaissance, the villanella and villancico (from the Italian villano, or peasant) were Italian and Spanish dance-songs. French poets who called their poems "villanelle" did not follow any specific schemes, rhymes, or refrains. Rather, the title implied that, like the Italian and Spanish dance-songs, their poems spoke of simple, often pastoral or rustic themes.

While some scholars believe that the form as we know it today has been in existence since the sixteenth century, others argue that only one Renaissance poem was ever written in that manner--Jean Passerat’s "Villanelle," or "J’ayperdu ma tourterelle"--and that it wasn’t until the late nineteenth century that the villanelle was defined as a fixed form by French poet Théodore de Banville.

Regardless of its provenance, the form did not catch on in France, but it has become increasingly popular among poets writing in English.

An excellent example of the form is Dylan Thomas’s "Do not go gentle into that good night":

Do not go gentle into that good night,
Old age should burn and rave at close of day;
Rage, rage against the dying of the light.

Though wise men at their end know dark is right,
Because their words had forked no lightning they5
Do not go gentle into that good night.

Good men, the last wave by, crying how bright
Theirfrail deeds might have danced in a green bay,
Rage, rage against the dying of the light.

Wild men who caught and sang the sun in flight, 10
And learn, too late, they grieved it on its way,
Do not go gentle into that good night.

Grave men, near death, who see with blinding sight
Blind eyes could blaze like meteors and be gay,
Rage, rage against the dying of the light. 15

And you, my father, there on the sad height,
Curse, bless, me now with your fierce tears, I pray.
Do not go gentle into that good night.
Rage, rage against the dying of the light.

Nevertheless

The Waking
I wake to sleep and take my waking slow.
I feel my fate in what I cannot fear.
I learn by going where I have to go.
We think by feeling. What is there to know?
I hear my being dance from ear to ear.5
I wake to sleep and take my waking slow.
Of those so close beside me, which are you?
God bless the Ground! I shall walk softly there,
And learn by going where I have to go.
Light takes the Tree; but who can tell us how?10
The lowly worm climbs up a winding stair;
I wake to sleep and take my waking slow.
Great Nature has another thing to do
To you and me; so take the lively air,
And, lovely, learn by going where to go.15
This shaking keeps me steady. I should know.
What falls away is always. And is near.
I wake to sleep, and take my waking slow.
I learn by going where I have to go.
--Theodore Roethke

Mad Girl's Love Song
I shut my eyes and all the world drops dead;
I lift my lids and all is born again.
(I think I made you up inside my head.)
The stars go waltzing out in blue and red,
And arbitrary darkness gallops in:5
I shut my eyes and all the world drops dead.
I dreamed that you bewitched me into bed
And sung me moon-struck, kissed me quite insane.
(I think I made you up inside my head.)
God topples from the sky, hell's fires fade:10
Exit seraphim and Satan's men:
I shut my eyes and all the world drops dead.
I fancied you'd return the way you said.
But I grow old and I forget your name.
(I think I made you up inside my head.)15
I should have loved a thunderbird instead;
At least when spring comes they roar back again.
I shut my eyes and all the world drops dead.
(I think I made you up inside my head.)
--Sylvia Plath