The rondeau began as a lyric form in thirteenth-century France, popular among medieval court poets and musicians. Named after the French word for "round," the rondeau is characterized by the repeating lines of the rentrement, or refrain, and the two rhyme sounds throughout. The form was originally a musical vehicle devoted to emotional subjects such as spiritual worship, courtship, romance, and the changing of seasons. To sing of melancholy was another way of using the rondeau, but thoughts on pain and loss often turned to a cheerful c’est la vie in the final stanza.

The rondeau’s form is not difficult to recognize: as it is known and practiced today, it is composed of fifteen lines, eight to ten syllables each, divided stanzaically into a quintet, a quatrain, and a sestet. The rentrement consists of the first few words or the entire first line of the first stanza, and it recurs as the last line of both the second and third stanzas. Two rhymes guide the music of the rondeau, whose rhyme scheme is as follows (R representing the refrain): aabba aabR aabbaR.

Where the rentrement appears in its traditional French form, it typically does not adhere to the rhyme-scheme--in the interest of maintaining the line’s buoyancy and force. But when nineteenth-century English poets adopted the rondeau, many saw (or heard) the rentrement as more effective if rhymed and therefore more assimilated into the rest of the poem. An example of a solemn rondeau is the Canadian army physician John McCrae’s 1915 wartime poem, "In Flanders Fields":

In Flanders fields the poppies grow
Between the crosses, row on row,
That mark our place, and in the sky,
The larks, still bravely singing, fly,
Scarce heard amid the guns below.

We are the dead; short days ago
We lived, felt dawn, saw sunset glow,
Loved and were loved, and now we lie
In Flanders fields.

Take up our quarrel with the foe!
To you from failing hands we throw
The torch; be yours to hold it high!
If ye break faith with us who die
We shall not sleep, though poppies grow
In Flanders fields.

The challenge of writing a rondeau is finding an opening line worth repeating and choosing two rhyme sounds that offer enough word choices. Modern rondeaus are often playful; for example, "Rondel" by Frank O’Hara begins with this mysterious directive: "Door of America, mention my fear to the cigars," which becomes the poem’s refrain.