Chaucer's descriptions from "The Monk's Tale" which best illustrates Fortune as unreliable is "And when men trust in her she then will fail / And cover her bright face as with a cloud."
The monk's tale fits the category of parable because it tells the results of different people's good and bad behavior.
The Monk tale is a series of tragedies which represents the news that the wealth and position is just an illusion. He refers through the example of many falling from high to low ends, such as the example of Lucifer falling from heaven. Through such example and stories, he continues to show the people who have fallen from grace.
Model of tragedies which Monk offers is a Boethian one that is which is a reminder of the versatility of the life itself, to bring on top to those who are crashing down on the grounds and that the tendency of the feminine, whimsical fortune to spin her wheels. Hence, it is a simple narrative and Boethian reminder that high status often ends inadequately.