On Troilus’s first letter to Criseyde, TC 2.1065-85

[Chaucer] manifests an interest in the technical aspects of writing formal letters in Troilus and Criseyde, when he describes Troilus's first letter to Criseyde. His description can be broken down into the five major parts of a Latin epistle: the salutatio, the captatio benevolentiae, the narratio, the petitio, and the conclusio. Troilus's salutatio reads:

First he gan hire his righte lady calle,

His hertes lif, his lust, his sorwes leche,

His blisse, and ek thise other termes alle

That in swich cas thise loveres alle seche.

After these salutations, Troilus "gan hym recomaunde unto hire grace," thus performing a vernacular captatio benevolentiae. The third part of a letter, the petitio, immediately follows, including the word "preyde," an Englishing of peto, from which petitio derives: "And after this ful lowely he hire preyde / To be nought wroth, thogh he, of his folie / So hardy was to hire to write." Troilus then moves into the fourth canonical part of a letter, the narratio, or main story the letter seeks to tell, signaling this subpart by his choice of verb ("telle" Englishes narro, the root verbal form of narratio): "And after that than gan he telle his woo." Finally, we read Troilus's conclusio or leave-taking: "And seyde he wolde in trouthe alwey hym holde; / And radde it over, and gan the lettre folde." Through Troilus's meticulous performance of the rules of dictamen writing, the Troilus evinces an interest in epistolary modes of writing and in rendering those modes into English.

Eleanor Johnson, Practicing Literary Theory in the Middle Ages: Ethics and the Mixed Form in Chaucer, Gower, Usk, and Hoccleve (Chicago, 2013): 67-68