The Wife of Bath Prologue and Tale is dealing with men and women relationship and status. Wife of Bath tried to prove that women could have the mastery over men.  She took her own marriage experiences as the first example.  The second example is in the tale that she told.  

The Wife of Bath, Alisoun, has been married five times, and is ready and waiting for her  sixth husband.  The first three were old and  
rich; they died after she would gain mastery  
over them.  Her fourth husband was young,  
but he had a mistress.  Jankin was her fifth  
and most favorite husband.  Once when Jankin  
was reading aloud from his Book of Wicked  
Wives, she tore a page from his book, and he  
knocked her down so hard that she was still deaf from it.  She pretended to be dying, and when he leaned over and asked for forgiveness, she knocked him into the fireplace.  They made up, and he gave her fully control of soverignty.  

After the long prologue, the wife of Bath told a tale of a young knight who raped a young maiden.  He must roam the countryside in search of what is it that women must desire? The young knight had exactly one year to find the answer to the question and return to King Arthur's court, otherwise, he would be sentenced to death.  The knight's journey didn't go well until one  day, he met a hag.  She said that she had the answer to the question.  Moreover, she insisted that the young knight had to give her whatever she asked  for.  The knight then agreed.  In the presence of the queen, the old woman stated that what women desire most is sovereignty over their husbands.  Nobody disagreed with the answer so the young knight was asked to marry the hag.  On their wedding night, the old woman proceed to lecture him on the trivial nature of appearance. Then gave the knight two choices: ugly by day, but loyal and faithful for the rest of the time; or beauty by day,  but disgraceful and unfaithful for the rest of the time.  The knight, truly perplexed by his entire situation, and told her to decide.  The woman rewarded him both.  

About her tale, of course, there are some  
teachings in it.  For instance,  
   

   1. The inner virtue is more important than 
outer beauty.  A noble deed makes people a noble man.  
   
    2. Respect old people.  

    3. Poverty is not guilt and sin. Although no one likes poverty, poverty is always a good friend of mankind.  The poorest people are the richest because they believe in God.  

For these teachings, of course, they have their positive side to teach   people; however, on the other hand, the Wife of Bath, Alisoun also wants to  argue in defense of her beauty and youth losing.  Although she has lost her beauty and youth, she still has the desire of sex and sovereignty and she always welcomes the sixth husband to come so she teaches people not to look down old and ugly women at least they are kind and loyal.