What time period does The Canterbury Tales take place in?

Geoffrey Chaucer is widely considered to be the father of English literature. Chaucer was born in 1343, just as the Middle Ages were coming to a close and the Renaissance was dawning. His work The Canterbury Tales looks back on the three hundred and fifty years that preceded his writing.
In those earlier centuries, Medieval society was divided into three distinct social classes:
Aristocracy
Clergy
Peasantry
This society was known as “feudalism” and it had a very strict hierarchy. There was virtually no movement between the classes and no chance to change one’s station in life.
Feudalism was structured like a pyramid. Kings were at the top, followed by nobles, knights, and peasants at the bottom. However, by the time Chaucer was writing, these strict lines were starting to erode. There were a variety of reasons for the demise of feudalism.
Rise of the Merchant Class
Both speed and accuracy of travel were improving. New goods were flowing into medieval cities; many new foods, spices, fabrics, and other materials were introduced. Exporting businesses grew exponentially with each passing year as well. So many new opportunities to provide goods and services arose that groups of merchants who produced the same sorts of goods (carpenters, for example) banded together for the first time to form guilds. These guilds could regulate prices within their speciality and monitor quality.
Expanding Knowledge
Traveling not only brought new goods home but also new ideas. Mathematics and architecture saw huge leaps in interest and application.
Oxford and Cambridge Universities were founded in 1096 and 1209 respectively. These were the first institutions in England devoted to secular learning; all previous higher education was through the clergy.
The Magna Carta
Drawn up in 1215 (but not fully implemented for another couple of hundred years) the Magna Carta establish trial by jury and legalized taxation. This led to a new profession: lawyers, who were a prominent part of society by Chaucer’s time.
The Black Plague
One of the final death blows to the long-held system of feudalism came in a single year. From 1348 to 1349, somewhere between thirty and fifty percent of the English population succumbbed to the Black Plague. A lack of workers led to a massive shortage of labor. Now workers could make more demands, and have them met, making them the most powerful they had ever been.