His surviving work comprises forty letters and some 300 poems, these dividing evenly between about 140 courtly poems (–), and the moral writing, in verse and prose, that accompanied and followed his conversion (). The entire corpus is unified by his inherent sobriety, didactic sententiousness, and stylistic virtuosity. A conflict between the inherited Romance tradition and his learned civic formation and logical, moral temper is already apparent in the 120 courtly sonnets, most of which he links, for the first time in the history of the sonnet, into cycles (five in all, three of them narrative), to probe the moral inconsistencies of the conventional love ethos. The 20 courtly
canzoni display a pioneering grasp of the difficult style of the
Provençal troubadours (
trobar clus). Following his religious awakening, the tone and subject of Guittone's poems shifted. He started to sign his works as Fra Guittone, and in the
canzone "Ora parrà s'eo saverò cantare" he refers to his previous love poems as foolish. A series of palinodes announce a muscular new assertion of the moral will, abandoning Love and embracing Christian ethics. They introduce a body of mature work, much of it in correspondence form, in which he preached an austere code of practical civic conduct to all ranks of contemporary central Italian society. This blunt and sober writing of his maturity is marked by formal inventiveness. His epistles in the vernacular display high mastery of
ars dictaminis, coupled with stylistic experimentation. The letters, without precedent in Italian, furnish an anthology of models for sermons and political speeches. He invented the double sonnet and perfected the
lauda-
ballata; he addressed the
communes of Arezzo,
Pisa, and Florence, and leading political figures like
Nino Visconti and
Corso Donati; and his exchanges with poets like
Chiaro Davanzati,
Guido Guinizzelli, and
Guido Cavalcanti point to a looming crisis of allegiances and styles in which Guittone's prosaic moralizing and dense style were to be the anti-model of the Tuscan lyric
avant-garde. == Legacy ==