Was Chaucer an outstanding author of the thirteenth century?

No, Geoffrey Chaucer was not an author of the thirteenth century. He was a major figure of the fourteenth century.

Here's a timeline to help:

* 1343: Chaucer was born.

* 1300s: Chaucer lived and wrote during this century.

* 1400: Chaucer died.

So, while Chaucer is considered one of the most important English writers of all time, he was not from the 13th century.