In the "Canterbury Tales" Geoffrey Chaucer describes an age that was much different to our own modern one in terms of social practices, customs and beliefs - and his depiction of them makes very entertaining reading. The church played a far more powerful role in influencing people, society and state than it does now, and was often accused of using religion and scare stories to cowe the people into submission, as well as improve their souls and chances of getting into heaven. These chances were improved still further if you were free enough, and well-off enough to to be able to gain more brownie points along the way in your path on earth! One way to avoid the dreadful fires of hell, torturing devils and evil smug looking gargoyles (replicated at every turn on churches!) was to undertake a pligrimage of repentance and forgiveness - such as the popular little jaunt to Canterbury!
I believe you are referring to the literary period in which Chaucer lived and wrote the story. I will give you his age as well, just in case ;)
Chaucer was born in the late 1340s, 14th century England. Medieval feudalism was the way of life, where land was either rented from a landlord or inherited, and the printing press had still not being created, for which The Canterbury Tales were at first circulated in original hand-written manuscripts.
Life in the early 14th century was hard, because the poorer classes had not choice but to remain so. There was no middle class, and the upper classes debauched in wealth. However, something happened that changed everything: The Black Death.
When the Black Death killed 1/3 of the European population, the land, crops, animals, and properties that were left by strains of entire dead families were taken by the poor who survived, giving them a chance to live better lives. Slowly, the working class began to be needed, since the aristocracy did very little for themselves. Paying systems made possible for many working class-men to build small fortunes, and a middle class was beginning to slowly but surely make way.
Chaucer was one of those lucky Black Death inheritors. He inherited a large estate from dead relatives and became quite wealthy. He then climbed up the social ladder by serving under King Edward III, and in the Hundred Years War. During his time, language was also a key elemement. While the courtiers used French as their official language, the Church used Latin. Chaucer chose to use English because it was becoming the trend among other poets, but it was mostly spoken only in London. London was a world of its own back in the day, as the court was in Westminster, away from the merchant capital.
As far as Chaucer then he grew up among merchants, Black Death victims, the court of King Edward III, and the Hundred Years War- This shows that he was quite a cosmopolitan, colorful, and experienced person, good enough to write a tale as Canterbury. He was a retired man when he began the Tales in around 1387-1390, making him around his mid 40's when he wrote them. At this age, he would have been considered an "old man" but he had a lot under his wing to back up the Tales.