This gender-bending tale strongly undermines the medieval belief in the natural hierarchy of male superiority over women. First, the tale's narrator is a strong, feisty woman who knows her own mind, has been widowed and remarried five times, earns her own money, and isn't afraid to say what she thinks. Second, she tells the story of a knight who ends up under the power of more than one woman. First, as a penalty for rape, King Arthur puts this knight in the hands of the queen, to do with what she will.
The queen sets up a situation in which the knight must think about women as more than sex objects: she insists he find out what women really want. This means he will have to engage with women as distinct humans with minds and souls, not as beings merged into their husbands.
The queen gives the knight a year and day to find the answer, and at the end he is desperate. Once again he finds himself under the power of a woman: he agrees to marry an old hag if she gives him the correct response to what women want. She tells him women want to rule their husbands. This is correct, and the knight marries the hag. She says she can be beautiful by day and ugly by night or vice versa. When he tells her to decide for herself, this is music to her ears, for it is allowing the wife to rule. As a reward, she tells him she will be beautiful all the time--and faithful.
The story shows that, from the point of view of women, the "natural hierarchy" of man over women was not natural. It illustrates through the knight that men and women get along better when women have power in a relationship. Finally, the Wife of Bath moves beyond only wishing to upset the male/female hierarchy: she challenges the whole hierarchy of a society based on birth. She states, "Christ wants us to claim our nobility from him, not our ancestors," a radical notion in those times.