The Canterbury Tales is one of the most important pieces of Medieval literature and, even today, its significance ought not to be understated. Here are some reasons why:

• Chaucer wrote The Canterbury Tales in Middle English, the vernacular of this historical period. This is significant because works of literature were usually written in French or Latin, to reflect the linguistic preferences of "those in power." (See the first reference link provided.)
• Through its many characters, The Canterbury Tales gives us a glimpse into the lives of people in fourteenth-century England. Moreover, because the characters are so diverse, we can learn about people who are usually absent from historical record, like a wife and a miller.
• The popularity of The Canterbury Tales has endured across the centuries. It's "lively style," "earthy characters," and interesting plot has made it just as popular today as it was in Chaucer's time. (See the second reference link provided.)