According to the Prologue of William Shakespeare's "Romeo and Juliet" the feud between the two families will only end with the deaths (or actually the suicides) of the children of the two families who "with their death bury their parents' strife."
At the beginning of the story, the Montagues and the Capulets are sworn enemies. But Romeo, son of the Montagues, and Juliet, daughter of the Capulets, will soon fall in love.
However, due largely to their families's disapproval of their love, the two end up killing themselves. It is only with their deaths that the two families promise to end their fighting.
In the prologue , it says , " doth with their death bury their parent's strife . " This means that their children's death ( Romeo and Juliet ) was the only way to bring peace to both family .
Two households, both alike in dignity,
In fair Verona, where we lay our scene,
From ancient grudge break to new mutiny,
Where civil blood makes civil hands unclean.
From forth the fatal loins of these two foes
A pair of star-cross'd lovers take their life;
Whole misadventured piteous overthrows
Do with their death bury their parents' strife.
Shakespeare's "Romeo and Juliet" begins with an expository prologue which summarizes the plot of the play for the audience. To quote from the e-notes study guide,
"It states that two families in Verona have been bitter enemies for centuries. The fighting has broken out again between the families. A child from each of the warring families [Romeo and Juliet] meet and fall in love, and it is the death of the children that finally ends the feud between the parents."
What ends the rage between the two families of Verona according to the Prorogue in the play Romeo and Juliet by W.Shakespeare is that:
Line 6: A pair of star-crossed lovers take their life.
Romeo is the Montague with Juliet being the Capulet. They fall in love in spite of the long standing feud between the two families which does not reach a resolution untill
Line 8: Doth their with their death bury their parents' strife.
It is not until both their children commited suicide that the parents realize what waste and destruction and decide to end the feud, "bury their parents' strife'.