It is often said that Chaucer's "Prologue" to The Canterbury Tales provides modern audiences with a glimpse of life during the Middle Ages:
The “General Prologue” re-creates a lively image of Chaucer’s world.
Another source notes:
...we are indebted to him for the most vivid contemporary description of fourteenth-century England.
The same source points out:
In Chaucer's day it was customary throughout Europe for members of all classes to travel to religious shrines...By using the device of a journey, it was possible to bring together quite naturally persons of varied occupations and diverse social rank, a rarity in medieval society. Thus Chaucer was able to present in his work a cross-section of medieval society...
This collection included the three groups that represented the prevalent social strata of medieval England: feudal, ecclesiastical and urban.
A "microcosm" is...
...anything that is regarded as a world in miniature.
In essence, the world represented in Chaucer's "Prologue" represents a smaller version of the bigger world. When studying the diverse members of the pilgrimage—people who at that time would never associate with each other except when traveling on a religious pilgrimage—Chaucer provides us not only with those found in everyday society, but he is also honest about some of the problems society faced because of these people. He entertains by pointing out typical human foibles of many of these people; though he does not judge, he provides us with information so that we can decide for ourselves that, for instance, most of the clergy (servants of the church) were crooks, rather than servants of the people. Without these kinds of details, we would not be able to see these individuals (and their shortcomings) so clearly. We also find that people in Chaucer's time are very much the same as they are today.
The clergy most often miss the important details of their calling. Each was supposed to take a vow of poverty and give all they had to the poor: a Christ-like behavior. The only exception is the Parson. The Monk, the Friar, the Nun, and the Pardoner are all interested in their worldly possessions. One owns a fine hunting horse; another has clothes, jewelry and a dog that eats better than the peasants; another sells pardons stolen from Rome and fake holy relics; two of these men (we infer) get women pregnant and then arrange marriages for them. Only the Parson has given all he has to help the poor, weak and afflicted in his parish. This gives a clear picture as to the struggle the Church had to keep its servants honest and faithful.
However, among all those in the story, there are also those to admire: the Knight has just returned from battle. He is extremely thankful for his safe deliverance home; so much so that without removing his armor, he embarks immediately to pay homage to God at the holy shrine at Canterbury.
On the other hand, the doctor is a quack. The Wife of Bath is a good woman, but has buried several husbands and is looking for another: the inference is that she has a healthy libido, and wore all of her dead husbands out.
Chaucer is considered by some to be the father of fiction—and literature—because of his gift to so clearly describe people he met on his travels who came from all walks of life, reflecting the values and behaviors of the whole world at large.
Adventures in English Literature, Harcourt Brace Jovanovich Publishers: Orlando, 1985.