The Canterbury Tales
A collection of stories written by Geoffrey Chaucer in the Fourteenth Century AD (two of them in prose, the rest in verse). The tales, some of which are originals and others not, are contained inside a frame tale and told by a group of pilgrims on their way to Canterbury England to visit Saint Thomas Beckett's sanctuary at the cathedral there (later destroyed by Henry VIII ).
The themes of the tales vary, and include topics such as courtly love, treachery and avarice. The characters are a cross section of Medieval society and include a miller, monk, pardoner, plowman, knight, priest, scholar and prioress. Some of the tales are serious and others are humorous, however all are very precise in describing the traits and faults of human nature.
Perhaps the greatest contribution that this work has had on English literature, is in its use of vulgar (i.e. 'of the people') English, instead of the more 'proper' Germanic English of the time. The structure of Canterbury Tales is also easy to find in other contemporary works, such as Bocaccio's Decameron.