Give some stream of consciousness and then the answer. The Canterbury Tales (Middle English: Tales of Caunterbury) is a collection of 24 stories that runs to over 17,000 lines written in Middle English by Geoffrey Chaucer between 1387 and 1400. In 1386, Chaucer became Controller of Customs and Justice of Peace and, in 1389, Clerk of the King's work. It was during these years that Chaucer began working on his most famous text, The Canterbury Tales. The tales (mostly written in verse, although some are in prose) are presented as part of a story-telling contest by a group of pilgrims as they travel together on a journey from London to Canterbury to visit the shrine of Saint Thomas Becket at Canterbury Cathedral. The prize for this contest is a free meal at the Tabard Inn at Southwark on their return.

Answer this question: when did chaucer begin writing the canterbury tales and when did he stop?
The important part for answering this question is: The Canterbury Tales (Middle English: Tales of Caunterbury) is a collection of 24 stories that runs to over 17,000 lines written in Middle English by Geoffrey Chaucer between 1387 and 1400.
Therefore, the answer is 1387 and 1400.