From the Norman-French conquest of England in 1066 until the 14th century, French largely replaced English in ordinary literary composition, and Latin maintained its role as the language of learned works. By the 14th century, when English again became the chosen language of the ruling classes, it had lost much of the Old English inflectional system, had undergone certain sound changes, and had acquired the characteristic it still possesses of freely taking into the native stock numbers of foreign words, in this case French and Latin ones. Thus, the various dialects of Middle English spoken in the 14th century were similar to Modern English and can be read without great difficulty today.
The Middle English literature of the 14th and 15th centuries is much more diversified than the previous Old English literature. A variety of French and even Italian elements influenced Middle English literature, especially in southern England. In addition, different regional styles were maintained, for literature and learning had not yet been centralised. For these reasons, as well as because of the vigorous and uneven growth of national life, the Middle English period contains a wealth of literary monuments not easily classified.

Allegory
In the north and west, poems continued to be written in forms very like the Old English alliterative, four-stress lines. Of these poems, The Vision of William Concerning Piers the Plowman, better known as Piers Plowman, is the most significant. Now thought to be by William Langland, it is a long, impassioned work in the form of dream visions (a favourite literary device of the day), protesting the plight of the poor, the avarice of the powerful, and the sinfulness of all people. The emphasis, however, is placed on a Christian vision of the life of activity, of the life of unity with God, and of the synthesis of these two under the rule of a purified church. As such, despite various faults, it bears comparison with the other great Christian visionary poem, La divina commedia (The Divine Comedy), by Dante. For both, the watchwords are heavenly love and love operative in this world.
A second and shorter alliterative vision poem, The Pearl, written in north-west England about 1370, is similarly doctrinal, but its tone is ecstatic, and it is far more deliberately artistic. Apparently an elegy for the death of a small girl (although widely varying religious allegorical interpretations have been suggested for it), the poem describes the exalted state of childlike innocence in heaven and the need for all souls to become as children to enter the pearly gates of the New Jerusalem.