The later Middle English period in English literature is noted for three movements: alliterative revival, courtly love from French paraphrases, and the work of Gower and Chaucer, whose innovation in narrative voice in The Canterbury Tales was as significant as his use of English for composing poetry.
One of the most celebrated of the alliterative revival is Winner and Waster. The anonymous poet's mastery of alliterative syntax and diction was unsurpassed, not even by William Langland's later and less formal, though more well known, Piers Plowman. Alliterative revival authors are often anonymous and developed their own poetic conventions rather than reviving the conventions of alliterative poetry from the Old English period. In attempting to write alliterative verse-paragraphs according to their new conventions, they had to rely upon diction, syntax, and vocabulary that was archaic (from Old English) or derived from local dialects.
[A poetic convention is a customary structural approach to a genre of poetry, for example Petrarchan octave and sestet structure for sonnets or a seven-line stanza of iambic pentameter for rhyme royal or a specified moral in a fable.]
Themes of alliterative verse may be difficult to separate from the subjects of the poems. The subject of Winner and Waster was unusual in that it was a courtly romance poem. Others dealt with Alexander the Great, as in Destruction of Troy. The themes, derived from Latin sources, were simply the "matters" of history, or the great events and personages of history. Morte Arthure, the story of King Arthur, addressed historical matters of England. The four most famous poems of the alliterative movement, bound together in one volume, include Sir Gawayne and the Grene Knight and Pearl, a dream vision poem--such as Chaucer wrote--written in elegiac verse.
The author of Grene Knight wrote about chivalric romance but with the thematic purpose of expounding upon morality. Pearl, uncharacteristically but skillfully written in stanzaic form, tells of the consolation for loss by death as a dream vision explains salvation. Langland's Piers Plowman has special interest because it is purportedly autobiographical of an obscure London cleric and because it was authored in London rather than in the north, where dialects are very different from the later dominant southern London dialect. Langland modified the syntax and diction of the alliterative form (modifying its conventions) to make alliteration more accessible to the greater field of Lonodn readers.
Poems of courtly love had a prominent place between 1350 and 1410, especially in the court of Richard II, where vernacular English was beginning to dominate over French. Themes of courtly love were among the influences on Chaucer's work. Chaucer and Gower are the two most enduring poets of the later Middle English period, especially Chaucer whose use of dream visions is exemplified in The Book of the Duchess. Chaucer's style developed over time, beginning with The Duchess, moving through to the exemplary Troilus and Criseyde, ending with the unfinished The Canterbury Tales.
His themes were widely diverse but seemed to crystallize most clearly on love, especially the French concept of "fine amour," or "fine loving." Gower, his contemporary and friend, differed from Chaucer in that his moral principals were always clearly expressed in his moral themes, whereas Chaucer understood and expressed more of the uncertainty of human psychology in his themes.