When Chaucer first began writing the dominant form of verse was the English four-beat couplet, probably derived from the French octosyllabic (eight syllable) couplet, though often more free in the number of syllables allowed in the line. Chaucer's earliest works were in this form. As an example, here is the beginning of The Book of the Duchess:
I have gret wonder, be this lyght,
How that I lyve, for day ne nyght
I may nat slepe wel nygh noght;
I have so many an ydel thoght
Purely for defaute of slep
That, by my trouthe, I take no kep
Of nothing, how hyt cometh or gooth,
Ne me nys nothyng leef nor looth. (BD 1-8)
The line is iambic (unstressed, stressed), but with variations -- the initial unstressed syllable omitted, as at the beginning of line 5 (purely), and the ordinary stress pattern reversed in line 6 (That, by). (The -e on slepe in line 5 is ellided, as usual before w-, and cometh in line 7 is, as usual in Chaucer, pronounced comth.) Yet the lines move smoothly, producing a sort of conversational tone.
Chaucer used this four-beat line for the last time in the House of Fame. He experimented with a variety of stanza forms in iambic pentameter (ten syllables, with five stressed syllables) and in The Legend of Good Women he used (for the first time in English) the iambic pentameter couplets familiar to every reader of The Canterbury Tales. Readers who know this form from later writers, such as Alexander Pope, should note that Chaucer's verses are not "heroic" or "closed" couplets (which end with a full stop) but rather what the sixteenth century critic George Gascoigne (Certaine Notes of Instruction, 1585) called "riding rime":
. . . a notable kind of ryme, called ryding rime, and that is suche as our Mayster and Father Chaucer used in his Canterburie tales, and in diverse other delectable and light enterprises . . . As this riding rime serveth most aptly to wryte a merie tale, so rythme royall is fiteth for a grave discourse. (Quoted from Elizabethan Critical Essays, ed. C. Gregory Smith, Vol I, p. 56 [Widener: 10467.44.2]).
Rime Royal (which Gascoigne calls "rhythme royal") is a stanza that Chaucer adopted in his middle years, when he was greatly influenced by the Italian writers, most notably Giovanni Boccaccio. This is the stanza Chaucer used in his great Troilus and Criseyde (which he based on Boccaccio's Il Filostrato). It consists of seven iambic pentameter lines riming ababbcc.
The double sorwe of Troilus to tellen, A
That was the kyng Priamus sone of Troye, B
In lovynge, how his aventures fellen A
Fro wo to wele, and after out of joie, B
My purpos is, er that I parte fro ye. B
Thesiphone, thow help me for t'endite C
Thise woful vers, that wepen as I write. C
(Troilus and Criseyde, Bk 1, 1-7)
Where Chaucer got the form is not known; it was never used in English before Chaucer. In French a similar stanza called chant royal sometimes appears in lyric poetry, and it has been held that Chaucer adopted the form from the works of Guillaume de Machaut (c. 1300-1377). Or Chaucer may have adapted the Italian ottava rime, which consists of eight eleven-syllabled lines. riming abababcc; Chaucer had used an eight line stanza (ababbcbc) in his Monk's Tale. To adapt ottava rima to a seven-line form he had merely to drop the fifth line.
The name "rime royal" is likewise obscure (the phrase is not used in Middle English; it first appears in Gascoigne, as quoted above). Those who derive the form from French take it that the name is based on the French phrase chant royal; others have held that it is so called because of its use by Chaucer's royal admirer, King James I of Scotland (1394-1437), in his The Kingis Quair (The King's Book). Gascoigne seems to have thought the name derived from its splendid character: "This hath bene called Rithme royall, and surely it is a royall kinde of verse, serving best for grave discourses."
Chaucer's followers agreed, and rime royal served as the domninant form for sophisticted narrative poetry from Chaucer's own lifetime until Shakespeare's Rape of Lucrece (1594).
In The Canterbury Tales the stanza is used in The Man of Law's Tale, The Clerk's Tale, The Prioress's Tale, and The Second Nun's Tale. All are "grave discourses," and all are works concerning the suffering of innocent victims. Chaucer's "riding rime" is not restricted to "merry" tales: The Knight's Tale is clearly a grave discourse, and The Physician's Tale concerns the pathetic fate of an innocent victim. However, it is notable that the use of rime royal is restricted to this group of tales. The only other tales in stanzas are The Monk's Tale (which deals in part with innocent victims, such as Ugolino and his children), and Sir Thopas (for which Chaucer employs the stanzaic form of the popular minstrel romances).