Quan lo rius de la fontana s’esclarzis, si cum far sol; e per la flors aiglentina el rossignoletz el ram volf e refraing et aplana son dous chantar et afina, dreitz es queu lo meu refranha. Stanzas, however, ‘sub una oda continua,’ are not the rule. ‘Quædam vero sunt,’ Dante continues, ‘dieresim patientes, et dieresis esse non potest, secundum quod eam appellamus, nisi reiteratio unius odæ fiat vel ante dieresim vel post vel utrimque.’ The criterion, therefore, of the possibility of a dieresis or volta is, first of all, that in the poem there should be certain groups defined musically by the repetition of the same melody, and metrically by the recurrence of the same rhymes and of verses of the same length. The volta can, as has been seen, be either before or after such a group, or between two different groups if both parts of a stanza are divided in this way. Dante gives the terms for all these combinations in the following words: ‘Si ante dieresim repetitio fiat, stantiam dicimus habere pedes, et duos habere decet, licet quandoque tres fiant, rarissime tamen. Si repetitio fiat post dieresim, tunc dicimus stantiam habere versus; si ante non fiat repetitio, stantiam dicimus habere frontem; si post non fiat, dicimus habere syrma sive caudam.’ These few words contain in a nutshell the whole theory of Italian, and, with some slight changes, also of Provençal, stanzas. It remains to enter into the special cases referred to by this rule. The first alternative Dante mentions is that of a division effected by the repetition of certain melodic and rhythmic phrases in the first part of a stanza. After these groups, which in this case are called pedes, a rest or volta becomes necessary; and after this a new melody begins, which lasts to the end of the stanza, and is called a cauda.[43] The following is one of the very numerous examples of a stanza consisting of two pedes and a cauda: 1. { Ai deus, ar sembles ironda, { que voles per l’aire, { qu’eu vengues de noit prionda { lai al seu repaire! Pedes 2. { bona domna jauzionda { mortz es vostr’ amaire, { paor ai quel cors mi fonda, { s’aissom dura gaire. { domna, vas vostr’ amor { jonh mas mas et ador Cauda { bel cors ab fresca color, { gran mal me fatz traire.