Why do you think Medieval authors, namely Chaucer, challenged the common outlook on women?
Through the works of these authors (such as Canterbury Tales) we can see evidence of Medieval authors writing about women in a new light, contrary to how they were spoken of during the Middle Ages.
I think you’ve answered your own question. Women were shown in a new light. The Miller’s tale is a clear example. it shows women controlling their sexuality and, in fact, being sexually aggressive. A heavy concept for those days.