The Parson's Tale seems, from the evidence of its prologue, to have been intended as the final tale of Geoffrey Chaucer's poetic cycle The Canterbury Tales. The "tale", which is the longest of all the surviving contributions by Chaucer's pilgrims, is in fact neither a story nor a poem, but a long and unrelieved prose treatise on penance. Critics and readers are generally unclear what rhetorical effect Chaucer may have intended by ending his cycle in this unlikely, extra-generic fashion.
In the prologue to the tale, the host asks the Parson for a fable (the form used earlier with such apparent success by the Nun's Priest) but the Parson refuses with a round condemnation of fable stories, saying instead that he will tell an improving tale in prose since he can neither rhyme nor alliterate. It is also of interest that the host seems to be in some doubt as to the identity of the Parson, since he asks him to introduce himself:
(Parson's Prologue, lines 22-5)
Some idea of Chaucer's intended structure for the Canterbury Tales may be gleaned from this "final" prologue. The host speaks of al myn ordinaunce (being) almoost fulfild and says that the company lakketh...no tales mo than oon. Since known tales do not exist for all of the pilgrims, and since none reach the projected total of four tales each outlined in the General Prologue, the host's remarks give a further indication of the way in which Chaucer's ultimate scheme for the cycle either was not realised or has not survived.
The subject of the parson's "tale" (or rather, treatise) is penitence. It may thus be taken as containing inferential criticism of the behaviour and character of humanity detectable in all the other pilgrims, knight included. Chaucer himself claims to be swayed by the plea for penitence, since he follows the Parson's Tale with a Retraction (the conceit which appears to have been the intended close to the entire cycle) in which he personally asks forgiveness for any offences he may have caused and (perhaps) for ever having deigned to write works of worldly vanitee at all (line 1085).